How Idaho Got Expansion: Proposition 2, the Sideboards and the Courts

Few Idaho policy fights have a paper trail as clean as this one. There is a ballot result certified by the Secretary of State, a published Supreme Court opinion, a numbered bill with a signing date, and a statute with an amendment history printed at the bottom of its page. This lesson gives the sequence and shows where each record lives, because the most common errors about expansion are errors of sequence: attributing a 2019 condition to the voters, or a 2025 law to the initiative, or the reverse.

As of October 2026 the law described here is current as written in the sources. Some pieces, especially the work requirement language in Idaho Code 56-267(6), take effect on dates that have not yet arrived.

Before 2018: the coverage gap

The Affordable Care Act of 2010 offered a bargain to every state. Medicaid would cover all adults under 65 with income up to 133 percent of the federal poverty level, with Washington paying nearly all of the cost. The federal subsidies for private insurance bought through the health exchange start at 100 percent of poverty. The two programs were designed to meet in the middle. In 2012 the U.S. Supreme Court made the Medicaid half optional for states, and Idaho did not take it.

That left a gap. An adult with income under 100 percent of poverty, in a state that had not expanded, earned too much for ordinary Medicaid, which then covered mainly children, pregnant women, parents with extremely low incomes, and people with disabilities, and too little for subsidies on the exchange. A 2018 report in Rewire News Group put the number of Idahoans in that gap at an estimated 78,000, most of them working. Treat that as an advocate-era estimate and a reporter's figure, because the exact size depended on who counted and how.

Idaho already had a safety net for the worst outcomes of the gap, and the existence of that safety net shaped the debate. The Catastrophic Health Care Cost Program, known as CAT, began in 1982 and has been state-funded since fiscal year 1994 under a 1991 law. It is set out in Idaho Code Title 31 chapter 35. Counties pay the first $11,000 of eligible claims in a 12-month period, and the state pays above that, according to the Division of Financial Management's FY2022 performance report. The program serves single adults 18 to 64 without children at home, which is nearly the same group that expansion would cover. County commissioners, who sign off on the county share, therefore had a direct stake in the 2018 vote. Later sections show what happened to CAT afterward.

How an Idaho initiative gets on the ballot

Idaho's constitution reserves to the people the power to propose and enact laws, and that power is described in Lesson 6 of the Idaho Constitution course. The Laws and Rules course explains the process step by step in its lesson on initiatives and referendums. For the 2018 cycle the requirements were these: sponsors needed 56,192 valid signatures, which was 6 percent of registered voters at the last general election, and they also needed signatures from at least 6 percent of voters in at least 18 of Idaho's 35 legislative districts. Signatures went to county clerks for verification and then to the Secretary of State.

The sponsors were Reclaim Idaho, a volunteer group whose organizer was Luke Mayville, and Idahoans for Healthcare. Their volunteers gathered signatures through the winter and spring of 2018, and the filing deadline for the November ballot was May 1. Ballotpedia, working from the Secretary of State's records, reports that the campaign submitted 75,134 verified signatures and cleared the district threshold in 21 of the 35 legislative districts. News coverage from April 2018 reported more than 56,000 signatures submitted by an April 30 handoff, which may describe the first hand-in rather than the later verified total; the sources here do not let me reconcile the two, so quote the verified figure and name its source. The initiative was certified for the ballot on July 17, 2018 and appeared as Proposition 2.

Step	Requirement or fact	2018 result
Signature total	56,192 valid signatures (6 percent of registered voters)	75,134 verified (Ballotpedia)
Geographic spread	6 percent in at least 18 of 35 legislative districts	Met in 21 districts
Ballot qualification	Certified by the Secretary of State	July 17, 2018
Election	Simple majority of those voting on the measure	November 6, 2018
Challenge	Original action in the Idaho Supreme Court	Regan v. Denney, filed November 21, 2018

Why the sponsors went to the ballot

The sponsors said openly that they turned to voters because they did not expect the Republican-majority Legislature to expand Medicaid. Reporters at the time noted that Idaho was one of 18 states that had declined the federal money. This matters for how you read the later history. The Legislature did not object to the idea of insuring this group so much as it objected to the cost and the federal strings. Its answer in 2019 was to accept the law and then attach conditions. Conditions imposed on a voter-approved law are a different thing from a repeal, and the difference defines the next seven years.

The 2018 campaign and the vote

The Secretary of State's certified canvass shows 365,107 votes for Proposition 2 and 237,567 against, out of 602,674 votes cast on the measure. That is 60.58 percent yes and 39.42 percent no. The statewide ballot count was higher than the measure count, since some voters skipped the question. Always report the percentage of votes on the measure rather than of all ballots.

Yes carried the largest counties, and no led in some smaller ones. A selection from the canvass shows the spread:

County	Yes	No	Yes share
Ada	131,918	57,475	69.7%
Bannock	19,239	9,884	66.1%
Bonneville	20,243	15,030	57.4%
Canyon	35,973	27,321	56.8%
Kootenai	28,374	27,875	50.4%
Idaho County	2,933	4,101	41.7%
Jefferson	3,589	5,176	40.9%

Kootenai County is worth a second look. It voted yes by 499 votes, 28,374 to 27,875, and the man who sued to stop the measure, Brent Regan, was chairman of the Kootenai County Republican Central Committee. Canyon County, home to Nampa and Caldwell, voted 56.8 percent yes. A reader who assumes that "rural Idaho" voted no will miss that a growing suburban county such as Canyon was solidly in favor.

Money in the campaign, and where sources disagree

The two support committees raised nearly $2 million combined, according to Ballotpedia and Wikipedia, though Ballotpedia lists about $1.78 million in contributions. The opposition committee was Work, Not Obamacare PAC, tied to the Idaho Freedom Foundation, which raised about $60,000. Ballotpedia's own text gives a spending figure of $65,713 for the opposition, so its sources conflict on that number. When you write about campaign money, use the primary record: the committees' reports on the Secretary of State's Sunshine system, covered in the Elections and Campaign Finance course. Secondary summaries differ by the way they count in-kind support and loans, and none of them is wrong to the cent in every case. The gap between them is the honest range.

What the initiative wrote into law

Proposition 2 created a new section of the Idaho Code, 56-267, titled "Medicaid eligibility expansion." The text as it stands in October 2026 has six parts. The original 2018 language covered the first few; the later amendments added the rest.

Part	What it says in plain terms	Added when
(1)	The state must amend its state plan to cover people under 65 with modified adjusted gross income at or below 133 percent of poverty who are not otherwise eligible	2018 initiative text
(2)	The state must submit plan amendments to CMS within 90 days	2018 initiative text
(3)	Coverage must not be delayed by waiver talks; the state may not adopt a waiver that lowers federal funding for this group below the 90 percent commitment	Confirm in the session laws (history line)
(4)	If the U.S. Supreme Court finds the 90 percent provision (Social Security Act 1905(y)) unlawful, the Legislature must declare the section void	Confirm in the session laws (history line)
(5)	If federal funding falls below 90 percent, the House and Senate health and welfare committees must review and recommend by the end of the next regular session; between sessions the department must offset the added cost until the Legislature acts	Confirm in the session laws (history line)
(6)	By December 31, 2026, the department must implement community engagement requirements under 42 U.S.C. 1396a(xx); new enrollees must show compliance for the three consecutive months before applying, and the department must disenroll current enrollees who cannot show compliance	2026, House Bill 913, session law chapter 334

The statute page records its amendments: the section was added in 2018 as Initiative Measure No. 2, then amended by 2019 chapter 318, 2025 chapter 118 section 6, 2025 chapter 192 section 4, and 2026 chapter 334 section 1, which is House Bill 913. The table assigns part (6) to the 2026 bill because the Capital Sun and DHW tie the work requirement language to House Bill 913; which amendment added each of parts (3) to (5) is something to confirm in the session laws. For a citation you can defend, open the session law chapters on the Legislature's site and read the exact words of each amendment.

The 133 percent and 138 percent question

The statute says 133 percent. DHW and news reports say 138 percent. Both are right. Federal rules for modified adjusted gross income (MAGI) programs, at 42 CFR 435.603(d), direct states to subtract an amount equal to 5 percentage points of the federal poverty level when they apply the income test to the group with the highest MAGI-based standard. In effect, a person can have income up to 138 percent of the poverty line and still pass a 133 percent test. CMS describes Idaho's expansion standard as 133 percent in its eligibility-level table and notes that its figures are MAGI-converted standards, while KFF and DHW express the practical limit as 138 percent. Lesson 3 does the arithmetic with dollars.

The courts: Regan v. Denney

On November 21, 2018, Brent Regan sued Secretary of State Lawerence Denney in the Idaho Supreme Court, asking it to keep Proposition 2 from taking effect. His argument was that the initiative delegated lawmaking power improperly to the federal government and to the Department of Health and Welfare. The case number is 46545. Intervenors defending the measure included the Idaho Medical Association and three individuals. The Court heard argument in January 2019 and decided on February 5, 2019. Chief Justice Roger Burdick wrote for the Court.

What the opinion held

The opinion decided two things. First, it held that Idaho Code 34-1809(4), the statute under which Regan had filed directly in the Supreme Court, is unconstitutional because the Legislature cannot expand the Court's original jurisdiction. The Court nonetheless took the case under its own constitutional authority in Article V, section 9, and relaxed its usual standing requirements because the claimed violation was urgent. Second, on the merits, it held that Idaho Code 56-267 is constitutional. The statute refers to specific sections of the Social Security Act, and the Court read that reference as adopting those federal provisions as they existed when the initiative was enacted. That means the statute does not hand lawmaking authority to the federal government, because Congress cannot change what Idaho adopted by amending its own law later. The Court dismissed the petition, denied the writ of mandamus and awarded no attorney fees.

A separate point to avoid confusing: some press coverage and several summaries describe the case as "premature" or "not ripe." In the Justia copy of the opinion, those words come from Justice Moeller's separate opinion, which concurred in part and dissented in part. A few short phrases there say the matter was not yet ripe because it was unclear what the Legislature would do with funding and implementation. The majority did not dismiss on ripeness. It reached the merits and ruled for the measure. When you cite the case, say that the Court upheld the statute, and attribute the ripeness language to the justice who wrote it. The Idaho Reports volume citation was not available in the text consulted for this lesson, so cite the case by name, docket number 46545 and decision date, and confirm the reporter citation in the Court's own records before you publish it.

The 2019 sideboards

After the court ruling, the Legislature faced a decision it had avoided for years. The 2019 session produced Senate Bill 1204, passed on April 5, 2019 and signed by Gov. Brad Little on April 9, 2019. The Senate had approved an earlier amended version 20 to 15, and the bill changed as it moved: Sen. Fred Martin, the original sponsor, withdrew his support after the amendments, and Sens. Steven Thayn and Mary Souza took over as sponsors. The bill as signed directed DHW to request waivers from CMS. Supporters called the package "sideboards" on the initiative, borrowing a term from legislators who wanted limits on the program's course.

Sideboard in S1204 (as signed)	What it asked of CMS	Outcome
Work, education or volunteer requirement	20 hours a week, aligned with SNAP reporting every six months	No federal approval (Idaho Capital Sun, March 19, 2025)
Exchange option for 100 to 138 percent of poverty	Let people stay on the private exchange with tax credits	No federal approval (same source)
Managed care	Move the group into managed care	Comprehensive managed care returned in House Bill 345 of 2025 (see below)
Substance use disorder data and referral	Collect data and refer enrollees to treatment	Outcome not confirmed for this lesson
Keep the 90/10 match	Review the program if the match falls	Compare with the trigger in 56-267(5); confirm in the session laws
Mental health waiver	Seek a behavioral health waiver	Outcome not confirmed for this lesson; see the Idaho Behavioral Health Transformation 1115 on Medicaid.gov
Review in 2023	Legislative review of the expansion	Outcome not confirmed for this lesson

The fiscal note for S1204 was prepared by a proponent, and it said so on its face. It estimated that the exchange option could save $3 million to $5 million, that managed care could save about $2 million, and that the work requirement would apply to about 11,000 people after exemptions and cost about $1.6 million a year in state funds plus $212,500 one time. These are the sponsors' projections, written before the federal agency responded. Idaho did not receive federal approval for the 2019 work requirement and exchange-credit requests, so the savings estimates were never tested. The same lesson applies to the 2025 fiscal note covered in Lesson 5.

What the sideboards did and did not do

The sideboards did not repeal anything or delay the start of coverage. The program began on schedule on January 1, 2020. The Legislature's choice to write waiver requests instead of changing eligibility meant that the federal government, not the Legislature, would decide whether the new rules took effect. When CMS did not approve them, Idaho's expansion ran for years in nearly the form voters wrote. The federal government under the 2025 reconciliation law then set a national work requirement of its own, which Lesson 6 covers. In that sense, the 2019 request found its answer six years later in a statute that applies to every expansion state, and not as a favor to Idaho.

The rollout: November 2019 to the early 2020s

Idaho News 6 reported on October 25, 2019 that Medicaid enrollment would begin November 1 and run through December 16, 2019, with coverage starting January 1, 2020. The DHW director has since written that enrollment began in November 2019 and coverage began in January 2020. A KTVB piece said just under 40,000 people applied in the first two weeks after enrollment opened. The exact date the application portal opened should be checked against DHW records if you need it for publication, because the most precise date comes from a television report and not from the department's own page.

The DHW director's essay on the rollout puts the December 2023 total at about 94,587 Idahoans in Medicaid expansion. Compare that with the 2025 and 2026 counts in Lesson 1: 89,400 in March 2025, nearly 79,000 in March 2026, and about 85,000 in July 2026 according to the state. The count was higher in December 2023 than in any 2025 or 2026 figure listed here. This lesson assigns no cause to the difference. Each figure needs its date and definition, and Lesson 9 shows how to ask for them.

What happened to CAT

Before expansion, new CAT cases ran at 584 in fiscal year 2017, 820 in 2018, 744 in 2019 and 698 in 2020, according to the Division of Financial Management's performance report. Medical payments were $19,995,842 in FY2018 and $19,445,579 in FY2020. DHW expected CAT caseload to fall by about 80 percent eventually but said it would take longer than a year or two to see that. The report's numbers give you the baseline before and during the transition, so any claim about county savings should be checked against later reports. This lesson has no figure for county dollar savings, and neither should a news story that lacks one. County officials who want to compare their own books to the state's should start with the Local Government course and the Elected Officials page on budgets and fiscal duty.

After the start: 2024 to 2026

Four events since 2024 changed the shape of the law, and a timeline helps keep them straight.

2024: the Legislature takes a veto

House Bill 398 of 2024 added a section (Idaho Code 56-270, later renumbered 56-272 on the legislature's site) and House Bill 345 of 2025 replaced it with Idaho Code 56-2201, "Legislative approval required." The current section bars DHW from pursuing a state plan change or a section 1115 or 1915 waiver that extends coverage to more people or groups, or raises state costs, unless the Legislature first approves it in statute. Programs already authorized in statute or in effect on July 1, 2025 are unaffected, and the department must brief the Medicaid legislative review panel on a schedule the panel's cochairs set. In practical terms, any future widening of coverage needs a bill.

2025: House Bill 345

House Bill 345, a House Health and Welfare Committee bill with Rep. Jordan Redman and Sen. Julie VanOrden as floor sponsors, was introduced on February 28, 2025, and Gov. Little signed it on March 19, 2025 with an emergency clause. It passed the House 61 to 9 on March 6 and the Senate 29 to 6 on March 11 (90 yes votes to 15 no), and the Capital Sun described the vote as almost entirely along party lines. The bill directed a move to managed care, told DHW to seek work requirements, created an exchange tax credit option, ended automatic renewals using public data and called for biannual redeterminations, and amended 56-267(5) to require the department to offset added state cost between sessions if the federal 90 percent share drops. Its fiscal note, prepared by a proponent, projected net savings of $15.9 million in total funds ($5.3 million general fund) in FY2026 and $27.2 million total ($9.0 million general fund) in FY2027 and each year after, with timing dependent on federal approval.

Gov. Little called the bill a "huge improvement" over an earlier bill that would have reversed expansion. Sen. VanOrden stopped that earlier bill in committee. It would likely have repealed expansion. This sequence matters for a fair reading: HB 345 passed as a compromise between repeal and the status quo. Critics argued that the compromise still shifted the program toward conditions that expansion's authors had not written. Supporters argued that it preserved coverage. Both arguments are about interpretation. Neither changes the vote counts.

July 2025: Congress sets a floor

On July 4, 2025, President Trump signed H.R. 1, Public Law 119-21, which added a national community engagement requirement for expansion adults 19 to 64 in Social Security Act section 1902(xx). It overlaps the Idaho policy. Under the federal law a state cannot waive it through a section 1115 demonstration, so a state waiver request for the same requirement has no force. Idaho's statute then needed to match the federal text, which is what House Bill 913 did in 2026.

2026: House Bill 913

House Bill 913, a Ways and Means Committee bill with Rep. Vander Woude as House floor sponsor and Sen. Julie VanOrden as Senate floor sponsor, introduced on March 17, 2026, adopts the federal requirements into Idaho Code 56-267(6) with a three-month lookback. The House passed it 59 to 9 with 2 absent on March 23, and the Senate passed it 28 to 6 with 1 absent on March 31. The Capital Sun described the Senate vote as party-line and counted the House opposition as Democrats plus Rep. Grayson Stone; the official tally on the legislature's bill page is the one to cite. Its statement of purpose said "no new fiscal impact" beyond the funds DHW asked JFAC for. Gov. Little signed it on April 10, 2026, and it took effect that day as 2026 Session Laws chapter 334. DHW's 2026 request included $1.87 million for work requirements, split between federal and state funds, and $1 million for twice-yearly eligibility checks ($900,000 federal and $100,000 general fund).

Reading the whole history critically

Three patterns recur in how this story gets told, and each can be checked.

• Who gets credit for a condition. The 2019 sideboards came from the Legislature, the 2025 work-requirement request came from the Legislature, and the 2027 work requirement is required by federal law as well as Idaho's. A statement like "the voters approved work requirements" is wrong on all three counts. A statement like "Idaho lawmakers imposed work requirements on their own" is incomplete after July 2025.
• What the courts said. The only appellate ruling covered here is Regan v. Denney, which concerned whether the initiative was an improper delegation. It did not address the later conditions. If someone says "the Supreme Court approved the sideboards," ask for the case.
• What projections became real. The $3 million to $5 million exchange savings and the $2 million managed care savings in the 2019 fiscal note never materialized, because the federal approvals never came. The projections in the 2025 note depend on approvals too. A fiscal note is a forecast by whoever wrote it.

The next lesson, Who Qualifies and Who Is Covered, puts the 133 and 138 percent figures into dollars. If you plan to testify or report on the expansion history, read the opinion in Regan v. Denney yourself first and write down the holding in one sentence of your own. That single sentence will carry you through most of the arguments you will hear this year.