One reason Republicans may be eager to repeal Obamacare is that they figure it won’t affect too many of their constituents adversely.

They may want to look more closely at the enrollment data.

And maybe an electoral map, too.

More than 20 million people now get insurance through programs of the Affordable Care Act. These people are spread across the country. This means, naturally, that plenty of them live in states that were key parts of President-elect Donald Trump’s majority in the Electoral College, or they have at least one Republican senator, or both.

This makes them of high political importance to the GOP.

Key Obamacare users to watch are the ones who buy private coverage on one of the law’s exchanges and who qualify for tax credits that offset premiums and (for some of them) out-of-pocket costs.

Without financial assistance or strong protections for people with pre-existing conditions, they would be the ones most likely to go without coverage.

In Florida this year, for example, there are roughly 1.6 million people buying coverage through healthcare.gov and receiving at least some financial assistance. In North Carolina, there are more than half a million such people. For Pennsylvania and Michigan, it’s near 300,000.

You can see the full breakdown in the chart below:

These numbers represent just one part of President Barack Obama’s signature health care law. They don’t include people buying coverage without financial assistance, either through the exchanges or on their own, directly from insurers.

These people tend to be more affluent and it’s safe to assume they are among the ones least pleased with Obamacare coverage, whether because of high costs, limited doctor choices, or both.

They might not mind losing what they have through Obamacare. In fact, it’s nearly a sure thing some would celebrate it.

But surveys have suggested that for all of the law’s very real shortcomings, and the legitimate grievances many people have with it, most Americans who have obtained private coverage through the exchanges or on their own still rate their insurance as good or even excellent.

The same goes for the millions who got coverage through Obamacare’s Medicaid expansion, which has made coverage available to people with incomes below or just above the poverty line in states where officials have gone along.

That may not matter in states like Florida and North Carolina, where expansion plans have run into intractable political opposition. But it’s going to make a big difference in the midwest states that Trump swept.

Pennsylvania, Ohio, Michigan, and Wisconsin all have expanded Medicaid eligibility now. So do Iowa and Arizona, for that matter. Most of those states have Republican governors, too.

Republicans aren’t promising simply to repeal the the law, of course. They have pledged to replace it with a scheme that, they insist, would be even better ― “great health care for much less money,” as Trump likes to put it.

But Republican leaders in the different branches of government have yet to agree on a detailed proposal, even though they have vowed to do so for more than six years. House leadership only came together behind a rough framework for reform a few months ago.

And even the better-developed plans, which conservative intellectuals have been refining for the past few years, would generally result in fewer people covered, less financial protection for those with insurance, or a combination of both factors. Independent estimates of proposals in circulation have consistently found the net result would be millions of newly uninsured ― maybe more than 10 million and maybe even more than 20 million, depending on the details.

Note that those numbers of people losing their Obamacare insurance from repeal would almost certainly dwarf the number of people who lost their old policies in early 2014, when insurers jacked up premiums and cancelled plans in order to comply with the health care law’s requirements to cover more people and a wider array of services.

And the vast majority of those people were able to find some kind of coverage instead.

In theory, Republicans could pass a replacement plan that would not leave so many people worse off. In practice, that seems unlikely, given that it would require committing the kind of federal dollars that Obamacare does ― and one of the GOP’s main goals is to downsize that commitment.

Republicans have also floated the idea of “repeal and delay” ― that is, passing repeal quickly but postponing the effective date for a year or two. Supposedly this would give Republicans time to craft a suitable replacement, while giving the people on Obamacare now more time to adjust.

But industry and state officials are warning that won’t work, either. Secretary of Health and Human Services Sylvia Burwell has already pointed this out in an interview with The Huffington Post’s Jeffrey Young this week.

The moment a repeal passes, all of these people say, insurers would begin to pull out of the existing markets, creating instability and causing a new wave of disruptions.