For starters, a wave of Republican senators went on the record to say that dismantling the health law should be a careful, deliberative process that ensures a replacement plan for the 20-some million Americans who could lose coverage once it goes away—a feeling echoed by President-elect Donald Trump during his predictably unpredictable press conference this morning. Most of these lawmakers have good reason for their newfound reticence: their constituents are reaping significant benefits from the Affordable Care Act’s Medicaid expansion.

Five GOP senators signed on to an amendment Monday that would essentially delay (although non-bindingly) the repeal process by about a month to give congressional committees more time to craft an alternative: Bob Corker of Tennessee, Bill Cassidy of Louisiana, Susan Collins of Maine, Rob Portman of Ohio, and Lisa Murkowski of Alaska. That’s on top of other Republican senators who have recently warned against a hasty Obamacare repeal sans a replacement (albeit for a range of reasons) like Kentucky’s Rand Paul, Arizona’s John McCain, Arkansas’ Tom Cotton, and Tennessee’s Lamar Alexander, who heads the influential Health, Education, Labor, and Pensions (HELP) committee in the Senate.

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With the exceptions of Corker, Collins, and Alexander (who hail from Maine and Tennessee), every Senator who has spoken out lives in a state that adopted Obamacare’s optional Medicaid expansion, which would be rolled back if the law is repealed.

The health law, as well as the Obamacare Supreme Court decision which ruled that states didn’t have to participate in the expansion, gave states the option to significantly expand Medicaid to cover poor, childless adults, with the federal government covering at least 90% of the expanded Medicaid tab (and 100% for the first three years).

Before Obamacare, Medicaid was largely a program that helped poor, working families with children. In some states, you couldn’t access the public health plan even if your income fell below the federal poverty threshold as long as you were a childless adult.

A number of red states have ardently refused to go along with the expansion. But Kentucky, Arkansas, Louisiana, Alaska, and other Medicaid expansion states have all seen massive drops in their uninsurance rates after adopting it, providing a boon in rural regions where many hospitals regularly see patients who can’t afford their care. There’s also significant evidence that this newfound coverage has allowed previously uninsured people to access all sorts of basic medical treatments that they never used before, according to the Kaiser Family Foundation (KFF).

The Medicaid expansion’s fate is now up in the air, as are the individual health insurance marketplaces established by Obamacare. But it appears that GOP lawmakers who are no fans of the ACA are contemplating what might happen to their constituents and health care providers if the health law disappears without an alternative.