President Donald Trump’s signature act increasingly looks like it would devastate his home state. The American Health Care Act would hollow out care, cost jobs and risk the health of vulnerable Americans. But it’s a last-minute amendment introduced by two upstate New York Republicans, Chris Collins and John Faso, that would do the most damage.

Sixteen states make counties pay a portion of Medicaid costs, with the rest coming from the states and the federal government. Fifteen of them somehow escaped being threatened by this train wreck. However, Reps. Collins and Faso, whose regions would likely benefit from the change, agreed to shaft the rest of New York in return for their votes. Trump and House Speaker Paul Ryan need every vote possible to get the bill over the finish line.

This amendment would let New York counties, which pay 13 percent of Medicaid costs, off the hook. But it wouldn’t provide a penny more to the state. Collins and Faso say the state can just pony up the extra $2.3 billion a year in revenue starting in 2020 or find magical savings.

Faso argues that the scheme would allow counties to reduce property taxes, but the amendment makes no such demand. Albany would make up the lost funds from taxpayers, or Medicaid spending would plummet.

The $2.3 billion-a-year cut from this amendment would be in addition to cuts of about $2.4 billion a year in Medicaid to New York that were already in the American Health Care Act, for a total of $4.7 billion. About 50 percent of Medicaid spending in New York goes to long-term care of elderly and disabled people.

The Trump-Ryan bill would likely cost about 1 million New Yorkers their Medicaid coverage, and hospital experts and advocacy groups say it would drive hospitals working on the margins out of business. The Catholic Health Association of the United States opposes the amendment. Deals have to be made to get legislation passed, and that certainly was the case with Obamacare. But the idea that New York Republicans from Trump on down would act so cravenly against the best interests of the Empire State is unacceptable.