This story is part of Stateline’s midterm election coverage.

Voters in three red states — Idaho, Nebraska and Utah — bucked their own Republican legislatures yesterday and approved the expansion of Medicaid, extending medical benefits to tens of thousands of low-income residents.

In Montana, which also had a citizen-initiated ballot question on expansion, vote-counting on the measure was still too early to determine the result. In that state, the initiative would have made permanent the Medicaid expansion, which the legislature passed on a temporary basis in 2015.

Medicaid expansion was a key component of the Affordable Care Act, known as Obamacare, which Congressional Republicans have unsuccessfully tried to repeal. The fight over the ACA revealed how the law has gained popularity in the years since passage.

“Nebraskans wanted action,” Nebraska Sen. Adam Morfeld of Lincoln, a Democrat, who helped organize the Insure the Good Life drive and served as a consultant to it, told the Omaha World-Herald. “They provided action.” The measure will extend benefits to nearly 90,000 people in that state.

In Idaho, where 91,000 would gain coverage, the initiative passed with over 60 percent of the vote. It had the support of the Republican governor, Bruce Otter.

That was not the case in either Nebraska or Utah, where Republican governors opposed expansion. The Democratic governor of Montana, Steve Bullock, supported the measure there. In Utah, 150,000 would gain access.

With those three states added to the list, 36 states plus Washington, D.C., have all approved Medicaid expansion, likely adding pressure on the remaining states to do so.

Last year, Maine became the first state where voters, as opposed to governors or legislatures, decided to expand Medicaid as originally laid out in the ACA.

That legislation, passed in 2010, required all states to extend Medicaid benefits to all adults earning up to 38 percent above the federal poverty line, which translates to an annual income of $16,753 or less. It required states that didn’t already do so, to extend Medicaid beneficiaries to low-income, childless and non-disabled adults.

But while upholding the ACA, the U.S. Supreme Court in 2012 gave states the option of opting out of Medicaid expansion.

In Montana, Democratic Gov. Steve Bullock in 2015 signed legislation expanding Medicaid, but that law sunsets next July. Uncertain that the Republican legislature would again pass expansion, Montana proponents gathered enough signatures to put an initiative on Tuesday’s ballot that would make the expansion permanent.

Medicaid, the health plan for the poor, is jointly financed by the federal and state governments. For new beneficiaries under Medicaid expansion, the federal match will be 93 percent in 2019 and 90 percent thereafter with the states responsible for the rest. For the regular Medicaid population, the federal match differs among states, but in no case is it less than 50 percent.

Studies have found that Medicaid expansion has produced jobs, particularly in the health care field, reduced the uninsured rate and increased economic security of low-income Americans.

Stateline is an initiative of The Pew Charitable Trusts that provides daily reporting and analysis on trends in state policy. Since its founding in 1998, Stateline has maintained a commitment to the highest standards of non-partisanship, objectivity, and integrity. Its team of veteran journalists combines original reporting with a roundup of the latest news from sources around the country. Stateline focuses on four topics that are key to state policy: fiscal and economic issues, health care, demographics, and the business of government.