Sen. Susan Collins is in the pressure cooker heading into a crucial vote on tax reform next week, targeted by protesters in Maine and Washington, lobbyists both for and against the bill, Republican leadership and health care advocates.

Progressive activists were arrested at Collins’ Bangor office on Dec. 4 and clergy were arrested at her Portland office on Dec. 7.

Collins voted for the Senate version of the tax reform bill early this month, but remained undecided during the reconciliation process between the House and Senate versions of the bill pending the fate of amendments she championed. She cheered their inclusion in the final version of the bill that was released Friday afternoon.

“Americans deserve a tax system that is fair, simple, and promotes economic growth,” Collins said in a statement she released on Twitter and her website Friday night. “I am pleased that the final tax reform bill includes all three of the amendments I authored, along with a number of provisions for which I strongly advocated, that will benefit lower- and middle-income families.”

The vote is expected to be razor-thin in the Senate, with Arizona Sen. John McCain in frail health and possibly not being present to vote. With Republicans holding a slim 52-48 majority, it only takes three defections for the tax bill to be stopped in its tracks.

Another Arizona Republican, Sen. Jeff Flake, remains undecided. He has previously raised objections about the bill adding to the deficit, and he also wanted immigration solutions to help “dreamers,” those in the U.S. illegally but who arrived here as children. But with the other possible holdouts — Sen. Bob Corker, R-Tenn., and Sen. Marco Rubio, R-Fla. — flipping to a “yes” on Friday, the Republicans might not need Collins’ vote to pass the tax package.

The $1.4 trillion tax reform package would add $1 trillion to the national debt over the next 10 years after accounting for economic growth — according to official congressional estimates — and slash the corporate tax rate from 35 to 21 percent. Business groups favor the tax cuts, arguing that they would spur the economy, while critics complain that the cuts are skewed to the wealthy, and that the cuts for individuals would expire after nine years while the corporate tax cut is permanent.

Collins has made it clear she wants to see two bills become law that would help stabilize the ACA’s health insurance marketplace, and for Congress to waive $25 billion in automatic Medicare spending cuts the bill would trigger. But the timing remains tricky, as it looks increasingly likely that the ACA stabilization bills would be brought up after tax reform is voted on early next week.

Collins said this week that she would be “much more comfortable” if the votes for ACA stabilization occurred before the tax reform vote. On Nov. 30, she told reporters in Washington at a Christian Science Monitor breakfast that having the ACA votes go first was “hugely important” to her.

The tax reform bill repeals the Affordable Care Act’s individual mandate, which would leave 13 million more uninsured and increase premiums by 10 percent, according to the Congressional Budget Office. The individual mandate requires that people who can’t get employer-based coverage buy health insurance on the individual market or pay a penalty. The mandate is a way to ensure that young, healthy people are in the individual market, keeping premiums down.

The fixes Collins touts would mitigate the mandate’s repeal with $5 billion per year for two years of reinsurance, which would help alleviate the cost spikes of having fewer young people in the insurance pools. Another bill, Alexander-Murray, would restore the “cost-sharing payments” to insurers that the Trump administration halted this year.

Annie Clark, a Collins spokeswoman, said “it’s our expectation” that next week, the two ACA fixes would be attached to a must-pass continuing resolution government funding bill.

And Clark said Collins wasn’t concerned that the Affordable Care Act amendments she supports might be in jeopardy now that the Senate appears to have the votes it needs to pass tax reform regardless of how Maine’s senior senator votes.

“We remain very confident in the agreements we have,” Clark said in an email Friday night.

Critics argue that House conservatives will balk at passing the Collins bills, and that House Speaker Paul Ryan was not part of any deal made between Collins and Senate Majority Leader Mitch McConnell. McConnell promised Collins that the bills would be voted on by the end of the year. McConnell and Ryan issued a joint statement on Dec. 1 promising to avoid the automatic spending cuts to Medicare.

But after tax reform passes, Collins would have much less leverage to make sure the bills are approved, critics have said.

“She is being played like a cribbage board,” Christina Foster of Peaks Island said, referring to the promises Republican leadership is making to Collins that Foster believes will be broken.

Foster was one of about 10 members of Peaks Indivisible, a liberal advocacy group composed of Peaks Islanders, who played cribbage in Collins’ Portland office Friday to protest the tax reform bill. Foster said they got to talk to Collins on the phone for five minutes but felt like the senator was likely to vote for tax reform despite their objections.

The two ACA bills have been the subject of several studies by health policy experts, but one analysis released Thursday indicates that the Collins-Nelson reinsurance bill and Alexander-Murray would, for two years, more than offset the 10 percent premium increases caused by the mandate’s repeal.

“This means that the package of provisions would more than offset the impact of repealing the individual mandate, and result in premiums that are roughly 10 percent lower,” according to Oliver Wyman Health, an actuarial consulting firm.

Oliver Wyman concluded that states could use the $5 billion in reinsurance money to leverage a total of $15 billion in federal money for reinsurance through waivers that would need to be approved by the Trump administration.

Larry Levitt, senior vice president of the Kaiser Family Foundation, which analyzes health policy, said the Oliver Wyman analysis is “conceptually correct” although it might be a “little optimistic” on how much federal money could be leveraged by states. Levitt said he attributes most of the premium benefits to the Collins-Nelson reinsurance bill.

“The Collins-Nelson bill would blunt the effect of premium increases of repealing the individual mandate, although there would still be coverage losses,” Levitt said.

But, Levitt said, the extra reinsurance funding is temporary, while mandate repeal is permanent. Levitt said that states could alleviate the potential 13 million who would lose coverage with mandate repeal by approving individual mandates on the state level, automatic enrollments or other “carrots” that would get people to sign up for insurance.

Topher Spiro, vice president of health policy at the Washington-based Center for American Progress, a progressive think tank, said the Collins package “does nothing” after two years. And he said that many states with conservative governments may balk at reinsurance programs.

“Will red states hostile to the ACA — which do not want to make the law work — act? It’s very uncertain,” Spiro said.

Staff Writer J. Craig Anderson contributed to this report.