The Montana legislature over the weekend gave final approval to the state’s Medicaid expansion plan, sending the bill to the governor’s desk for a signature. The state senate passed the bill on Saturday, ending a years-long battle to expand public insurance in the state despite well-funded opposition by the conservative billionaire Koch brothers.

Democratic Gov. Steve Bullock, who is expected to sign the bill, praised the passage of the Montana Health and Economic Livelihood Partnership (HELP) Act, saying that “Democrats and responsible Republicans stuck together and shepherded the bill to final passage.”

The HELP Act, seen as a compromise between conservative and liberal lawmakers, will expand Medicaid eligibility up to 138 percent of the federal poverty level, or an income of about $16,200 for an individual, as outlined by the Affordable Care Act. It will also require enrollees to pay monthly premiums and co-pays, and would give people the option of participating in “employment or reemployment assessment” programs.

State estimates have put the number of people likely to sign up for Medicaid somewhere between 27,000 and 45,000, according to the Montana Standard. Less than a million people live in Montana.

Only a few other state legislatures, such as GOP-dominated Indiana and Utah, have looked to tie Medicaid expansion to employment, a tactic that has gotten conservatives on board with expansion plans.

Montana lawmakers have for years tried to expand the public insurance. In 2013, the Medicaid expansion bill was defeated by a single vote after Democratic Rep. Tom Jacobson, who supported the bill, accidentally voted against it.

This year, the measure faced obstacles toward the end, when a house committee added a last-minute amendment to the bill that angered Democrats. The so-called poison pill amendment, introduced by Montana Republicans, would have altered oversight committee selection procedures and instituted a pilot program focusing on behavioral change strategies for those who receive the most Medicaid benefits.

The amendment was eventually removed, after a series of procedural maneuverings.

The house held nine floor votes related to the bill before sending it to the senate for approval.

“The Montana bill had been declared dead a few times now, but there was more momentum that was apparent from the outside,” Katherine Howitt, a senior policy analyst for the Community Catalyst, told Politico.

The bill’s passage marks a defeat for the Koch brothers, who have thrown resources into campaigns against insurance expansion in Montana and other states. In Montana, a state where Republicans control both the house and senate, the Kochs sent staffers from the right-wing group Americans for Prosperity to hold town halls across the state to trumpet the supposed perils of Obamacare.

“They flew in a bunch of high-priced young politicos from Washington to get the job done,” Eric Stern, Montana’s deputy secretary of state, wrote in Salon. “These held ‘town meetings’ in rural communities at which they showed up in slim-fit suits and pointy shoes, looking like they were heading to a nightclub, lecturing farmers and ranchers on politics and the dangers of ‘more Obamacare’ and publicly threatening moderate Republicans. It didn’t take long for them to get booed off the stage by their own partisans.”

Officials from the Montana Human Rights Network led the charge to flood lawmakers with calls supporting the state’s Medicaid expansion in the days before the legislature took action.

With Bullock’s signature, Montana will become the 29th state, plus D.C., to expand Medicaid under the Affordable Care Act, and the second state to do so this year.

Indiana’s Republican Gov. Mike Pence signed a Medicaid expansion bill into law in January. Other Republican-majority states, including Florida, Utah, and Alaska, have also considered expansion this year.

The federal government will also have to sign off on the expansion before it can take effect.