Supporters of Medicaid expansion celebrate their victory in Portland, Maine. (AP Photo/Robert F. Bukaty)

This post has been updated. 

Less than two months after Republicans' latest effort to repeal the Affordable Care Act imploded, Maine voters overwhelmingly decided to expand Medicaid to tens of thousands of people.

But the state's Republican governor, Paul LePage, seems determined to stop the measure from going into effect, setting the stage for a legal battle that could reverberate across the nation.

LePage issued a statement Wednesday saying he will open Medicaid to new people only if the state legislature fully funds it without raising taxes, without pulling from the state's rainy day fund or without taking money from the elderly or disabled. That's despite the fact Maine residents voted on the initiative knowing it would likely raise taxes.

"Credit agencies are predicting that this fiscally irresponsible Medicaid expansion will be ruinous to Maine’s budget," LePage said.

Supporters of the ballot measure say that LePage has no choice but to implement it.  He can't veto it.And even if he could, top officials in the state legislature say they're willing to figure out a way to fund it.

By mid-August, a new group of qualifying Mainers should be able to enroll in Medicaid. If they can't, LePage could open himself up to a lawsuit. Once a state elects to participate in the Medicaid program, as Maine has, that state is legally bound to comply with federal law.

LePage's office did not respond for comment on the potential for a lawsuit. LePage has vetoed a bipartisan legislative deal to expand Medicaid under the Affordable Care Act at least five times during his six years in office, and he's supported congressional Republicans' various plans to roll back Obamacare and significantly cut funding for Medicaid. Maine Sen. Susan Collins (R) was one of the defining “no” votes that ultimately ended the GOP efforts, saying the plans would pull the rug out from too many in her state.

LePage's refusal to expand the program except under very specific conditions throws down a significant roadblock in what was supposed to be an unmitigated success for progressives. Maine was the first state Tuesday to expand Medicaid by ballot box, and it won by nearly 20 percentage points.

Progressives were hoping their victory in Maine could give them a shot of momentum to expand the program in other states. In Alaska and Idaho, groups have already started similar Medicaid expansion ballot initiatives for next year.

"The initiative passed by at least 59 percent," said Jonathan Schleifer, executive director of the Fairness Project, which helped put together the ballot initiative. "LePage won his most recent reelection by 48 percent. It's clear what and who the people support." He said his organization will support legal action to try to get the Medicaid expansion implemented.

The Fairness Project has spent the past year in Maine —  and a sizeable chunk of the $2 million spent on the expansion — laying the groundwork to expand Medicaid. After Trump won the election and Republicans held on to Congress, they went to their tried-and-true method of ballot initiatives to push back.

The left has had spectacular success over the past four years going around Republican legislatures to change state policy on everything from guns and minimum wage with ballot initiatives. In fact, when put to the voters over the past 20 years, minimum wage increases have rarely lost.

Last November was no different. Voters in four out of four states resoundingly approved minimum wage hikes in 2016 (including Maine, where voters approved one of the highest minimum wages in the nation).

In Arizona, the vote for a high minimum wage outperformed Trump by 10 percentage points. Voters in eight of nine states also voted to ease restrictions on marijuana, and three of four states voted to put in place gun restrictions.

Ballot initiatives are an important tool for progressives in the Trump era, much like how conservatives used them in the '90s when Democrats dominated government. Other national groups descended on Maine to help this pass. Planned Parenthood's Maine political group said they knocked on over 8,600 doors in Portland over the last week of the election.

Not all progressive ballot advocates are as bullish on Maine's ability to change the health-care landscape.

Kellie Dupree with the Ballot Initiative Strategy Center, which helps progressive groups strategize ballot initiatives, said expanding Medicaid can be a tough sell as it requires taxpayer money.

“We'll wait to see how these policies shape up,” she said before the vote took place.

Advocates will also have to see if, in Maine, they can actually get the expansion implemented.

Correction: This post originally suggested the Fairness Project gave $2 million to the Medicaid expansion campaign. $2 million was the total spent on the campaign; Fairness Project gave about $375,000.