TPM’s checklist of those who support or oppose House Speaker Paul Ryan’s phaseout of Medicare has been updated to show that Claire McCaskill is positioning herself as part of the opposition “according to a TPM reader who called her office.” She was quoted on an NPR local news spot today saying that she opposed the Ryan plan. We need to give her kudos and lots of support for taking this position. I’ll be calling and writing her to thank for her for making this unequivocal statement, and I hope lots of others do so too.

But, as well, I’ll be asking some questions about her level of commitment to Medicare.

Keep in mind that McCaskill is speaking to the Ryan privatization plan exclusively. In the past, in her deficit alarmist persona, she has signed on to benefit cuts and other mechanisms for restructuring the program. In 2013 she and GOP Senator Tom Coburn of Oklahoma introduced legislation that would institute Medicare means-testing to raise co-payments and co-insurance. We need her to elaborate on just what type of future she is supporting for Medicare.

Keep in mind, too, how she takes progressives for granted and tries to impress conservative Missourians with her “independence,” leaving her open to poorly considered, one-sided “bipartisan” initiatives. She confirmed today that she’s definitely running in 2016, probably against Rep. Ann Wagner (R-2), who will, given the lay of the ground in this northernmost outpost of the Trump confederate empire, be a tough challenge. And how has McCaskill responded to such challenges in the past. With more of the “independence” GOP-lite chatter.

A New York Magazine article by Ed Kilgore entitled “Why there Probably won’t be a ‘Tea Party of the Left'” offers a disturbing take on the forces that are in play around McCaskill:

The obvious targets for either a bipartisan Trump outreach or for disciplinary efforts by progressives are the Democratic senators up for reelection in 2018 who represent states carried by Trump. There are ten of them: Bob Casey (Pennsylvania), Joe Manchin (West Virginia), Bill Nelson (Florida), Sherrod Brown (Ohio), Debbie Stabenow (Michigan), Joe Donnelly (Indiana), Tammy Baldwin (Wisconsin), Claire McCaskill (Missouri), Heidi Heitkamp (North Dakota), and Jon Tester (Montana). You might imagine some of these states are not reliably Republican in the future, but the flip back to the Democrats won’t be automatic, either, in a midterm election when the turnout dynamics have recently favored Republicans.

Now, Sherrod Brown and Tammy Baldwin and probably Debbie Stabenow are not the sort of Democrats who will be hankering for a way to show Trump voters they’re not all bad, and Bob Casey has his own appeal to white working-class voters that doesn’t necessarily depend on bipartisanship. But the rest of these vulnerable Democratic senators could waver.

And if they do, what exactly is “the tea party of the left” going to do about it? Joe Manchin, for one, would probably pay for left-bent protests against his “centrist” heresies in West Virginia, and would definitely welcome a progressive primary opponent to triangulate against. Heitkamp’s state went for Trump by 36 points; Tester’s, McCaskill’s, and Donnelly’s by 20 points or slightly less. Does anyone think a candidate more progressive or partisan than any of these worthies has a prayer of carrying their states in the immediate future?

At some point, would-be members of a “tea party of the left” need to come to grips with the fact that the “tea party of the right” had more geographical material to work with. …

This narrative is the sort of thing that has resonance with politicians – and for good reason. Prospects for the type of opposition party solidarity that we need if we are to hold off and undo the damage done by the Trump election may very likely be undermined by politicians like McCaskill who are not only skilled at playing the odds, but believe it is their only option apart from self-sacrifice.

But then again, nothing’s ever a done deal until its done. McCaskill might surprise us all and go down trying to hold the bridge. She might not even go down if she gets some help and does a good job on that bridge.