Ady Barkan sat in a wheelchair on Capitol Hill, his words amplified by a human megaphone. His voice weak from the effects of the neurodegenerative disease amyotrophic lateral sclerosis, or ALS, the 34-year-old activist was flanked by fellow organizers protesting the GOP tax bill in the Hart Senate building, who repeated him in unison.

“I have ALS. I am dying,” Barkan said. “But when we come together our voices echo so loud through the halls of Congress, out to the Supreme Court, up Pennsylvania Avenue, all the way to Wall Street.”

A few minutes later, Barkan was arrested by Capitol police for his role in the protest. As he was led away, he walked slowly, leaning on a cane for support. Barkan is no stranger to activism; he’s worked for the progressive group Center for Popular Democracy for five years. But ever since his ALS diagnosis last year, his fight against the GOP tax bill has become deeply personal.

ALS is a terminal neurodegenerative disease that causes a person’s muscles to atrophy. The symptoms vary from person to person; some lose their speech first, while others’ mobility lapses first. ALS patients typically die within three to five years of their diagnosis. Others, including renowned physicist Stephen Hawking, live for decades with the disease.

Barkan was diagnosed with ALS in October 2016, about three months after he noticed his left hand was too weak to shuffle a deck of cards. Before then, he was a healthy young father who went for runs regularly. In the past year, his disease progressed rapidly, limiting his ability to walk or move his arms. He can no longer pick up his son Carl, a toddler with a curly head of hair who recently started to walk and talk.

Eventually, Barkan will need a ventilator to help him breathe and a feeding tube after he’s no longer able to swallow food on his own.

“If I can’t get a ventilator, I won’t live,” he said. “It’s expensive to have a ventilator and have the care you need to accompany it.”

In recent weeks, Barkan has become the face of the protest movement against the GOP tax bill. Unlike the fight over Obamacare repeal, the tax debate has been more challenging for activists to message around. To many people, tax cuts for America’s corporations and wealthy are abstract, even if they are unpopular. Congressional Republicans, desperate for a big legislative “win” this year, are charging ahead. But it’s people like Barkan who are trying to remind lawmakers that the tax bill has real and human consequences — in his case, through potential cuts to Medicare the bill could trigger.

Barkan’s remaining time is limited, and he’s using it to fight.

“Everything is harder,” Barkan said. “Getting in and out of the van where they put you, getting up and down from the chair to walk to fill out my Miranda rights form. Carrying my stuff back to the hotel from the jail. Standing in the cold last night. But those are minor problems at the moment.”

How the tax bill could impact Medicare recipients

Barkan currently gets health insurance through his employer, covering most of his ALS care, but when he becomes too sick to work, he will have to go on Medicare. The Republican tax bill contains about $1.5 trillion of tax cuts, and is expected to increase the national deficit by about $1 billion. If that happens, it could trigger an automatic $25 billion cut to Medicare, due to a 2010 “pay-as-you-go,” or PAYGO law, as Vox’s Tara Golshan explains:

If Republicans want to pass a tax cut, they have to pay for it with mandatory spending cuts — or, inversely, if Congress boosts funding for entitlement programs, it has to increase taxes. Medicaid, Social Security, food stamps, and all social safety net programs are exempt from this sequestration. But Medicare, the Social Services Block Grant, student loans, and mandatory spending in the Affordable Care Act (other than exchange subsidies and Medicaid expansion), among others, would all be on the chopping block.

Some Republicans are saying this won’t happen. Maine Sen. Susan Collins got to “yes” on the tax bill in part by getting “written assurances” from leadership that Republicans would pass other legislative measures to counter the effects the tax bill might have on health care. (These assurances won’t actually solve many of the underlying problems the bill creates, as Vox’s Dylan Scott explains.)

If Congress can’t pass a PAYGO waiver and Medicare funding is cut, it doesn’t mean that Medicare patients would lose their eligibility or benefits outright. The cuts would impact patients differently: by potentially reducing the payments the federal government makes to doctors and hospitals. That means doctors could start turning away their Medicare patients if the insurance money isn’t there, advocates fear.

“They may decide they’re not going to see Medicare beneficiaries anymore,” said Dan Adcock, director of government relations and policy for the National Committee to Preserve Social Security and Medicare. “It could potentially limit the person’s choice of providers.”

That’s a problem for any Medicare recipient, but especially for people like Barkan who have complex illnesses that demand highly specialized care and equipment. ALS is an expensive disease that needs entire teams of specialty doctors to manage and treat; it also requires a lot of in-home care, normally covered by Medicare.

There is a real fear among advocates that these cuts will hasten a trend that already exists in Medicare; older and chronically ill Medicare patients who are being denied coverage if their health doesn’t improve.

“We have seen changes to the way that Medicare pays for such services ... that in our view incentivize providers to steer clear of folks that need ongoing care,” said David Lipschutz, senior policy attorney for the Center for Medicare Advocacy.

Legislation to stop the PAYGO cuts from going into effect will take 60 votes, meaning both Democrats and Republicans must sign on for it to pass. That seems possible, but not certain. On the one hand, Democrats could try to pin PAYGO cuts on the GOP to demonstrate the effects of the tax bill. On the other hand, the health insurance of millions is at stake.

“It’s hard to prognosticate and guess at what’s going to happen,” said Lipschutz. “It’s quite possible those cuts will go into effect.”

A personal plea to GOP senators

Barkan has spent the last seven years as a professional activist, and five with the Center for Popular Democracy. He knows how to stage a protest, schedule meetings with lawmakers, and document everything to upload to social media. Taking a short break in his hotel room last week, Barkan switched between doing interviews, scheduling more on national television, and planning for meetings with senators on Capitol Hill.

Besides meeting with Democratic senators, Barkan has been trying to schedule sit-downs with Republicans to convince them to vote “no” on a final tax bill: Sens. Jeff Flake (AZ), John McCain (AZ), and Susan Collins (ME).

The family is spending their days doing media appearances, and leading protests — at times, against the advice of Barkan’s doctors. He hasn’t been sleeping much lately, and is fighting off a head cold, which only serves to make him weaker.

“Yeah, it takes work and it would be easier to stay in the hotel room and sleep,” he said. “But if we’re going to save this country, we have to work hard at it and sometimes make some personal sacrifices.”

Even with his experience in activism, Barkan’s story went viral by chance, when he bumped into Sen. Jeff Flake on a plane home from Washington DC. Their 11-minute conversation, filmed by the woman sitting next to Barkan, included moments where Flake expressed dismay about the lack of regular order in the Senate on taxes, and explained why he ultimately voted yes, in exchange for an assurance to be part of immigration negotiations.

Barkan urged him to vote “no” on the final bill being negotiated between the House and Senate, which was released Friday and is slated for a vote this week.

“You can be an American hero, you really can,” Barkan told Flake. “You’re halfway there. If the votes match the speech, think about the legacy that you will have for my son, and your grandchildren, if you take your principles and turn them into votes. You can save my life.”

Barkan and activists from Maine met with Collins last Wednesday. After Collins helped defeat the Republican bill to repeal Obamacare, some hoped she might do the same for the tax bill. But here, Collins has proved to be tricky.

She’s adamant about voting for the tax bill before the end of the year, in exchange for assurances from Republican leadership about passing a bipartisan bill to stabilize the Obamacare insurance exchanges and making sure the Medicare spending cuts that would impact Barkan wouldn’t go into effect.

When Collins and Barkan met on Wednesday, the senator told him she was satisfied the funding wouldn’t be cut. Barkan said he believed she was being duped.

“You have to protect us before you vote ‘yes,’” he said. “They’re lying to you.”

Collins calmly and quietly pushed back, saying she did not believe a vote should be delayed to 2018 to include Alabama’s newly elected Democratic senator Doug Jones.

“I do not believe that I’ve given up leverage,” she told activists. “I’ve used my leverage to negotiate agreements that are promises to me. I’m sorry that you don’t believe in the agreements.”

Barkan said he was disappointed in the meeting with Collins, adding he was surprised the moderate senator was siding with her party so strongly on taxes.

“Why not insist that you get paid first before you give someone your merchandise when they have a history of not paying their bills?” he asked. But he remains hopeful that Collins and Flake will change their minds. By speaking to them in his wheelchair, with his strained voice and refusal to yield, Barkan hopes he can change their minds.

“I hope they see my humanity, and I hope that they decide to prioritize people like me, rather than their wealthiest donors,” Barkan said.