The answer is, laugh in their faces. The G.O.P. recently rammed through a tax cut, disproportionately benefiting the wealthy, that will probably cost $2 trillion over the next decade — with no offsetting savings. Enhanced health care could easily be paid for by rescinding just part of this big giveaway. If Republicans won’t do that, it’s not Democrats’ problem.

And if this proposal’s advocates are willing to be relaxed about funding, as they should be, the plan is basically ready to go. If Democrats take the Senate and the White House next year, they could enact the plan, easing the burdens of millions of Americans, almost immediately.

What about progressive hopes for a more fundamental health care overhaul? Representative Alexandria Ocasio-Cortez got it exactly right: While still calling for hearings on “Medicare for all,” she declared herself “happy to support any provision that strengthens the A.C.A. and plugs some of the gaps that we’re seeing.” (So far, Bernie Sanders has refused to support the plan. Let’s hope he walks that back.)

So Democrats have a realistic plan to expand health care, while Republicans are still pursuing their jihad against Obamacare. The question is why.

We have, after all, gone well beyond the point where trying to kill the A.C.A. was a smart if cynical political strategy. The act has become increasingly popular since Trump took office. Health care was central to the 2018 midterms, and 75 percent of voters who considered it the most important issue voted Democratic.

So why can’t the G.O.P. just cut its losses and accept that Obamacare has become part of our social fabric? After all, there was a time when people like Ronald Reagan insisted that Medicare would destroy American freedom; these days Republicans pose as defenders of the program (even if they’re still trying to undermine and privatize it on the sly).

Well, political scientists have some interesting thoughts about the reasons the G.O.P. won’t just throw in the towel on the A.C.A. But details aside, modern Republicans just hate the idea of using public policy to help Americans get the health care they need, even when people’s inability to get insurance is a result of pre-existing medical conditions over which they have no control.