Apparently, the explanation of the moment on Capitol Hill for why Toomey-Manchin failed is that Senators didn’t think they could hold controversial positions on too many issues at the same time. Embracing gun control, gay rights, and immigration reform is too heavy a lift. This morning, Ezra Klein points us to one unnamed Senator who told the White House he is being pushed too hard:

“Guns, gays and immigration — it’s too much. I can be with you on one or two of them, but not all three.”

Meanwhile, Senator Joe Manchin, who tried to round up votes for his compromise on background checks, is on the record saying he has heard similar complaints from multiple Senators. So this really does appear to be a real and widespread rationale. Klein comments:

It’s rare that the psychodrama of the Senate comes on such full display. But to state the obvious, this isn’t just an explanation for a vote. It’s a salve for a guilty conscience. This is not the sort of rationalization that would be leaking from the chamber if senators were confident they’d done the right thing. It’s a rationalization for people who feel they did the wrong thing, and want to tell themselves it’s the cost for doing the right thing later, on an even larger scale.

As Klein concludes, this is rooted in a rather low standard for what constitutes “political courage.” Meanwhile, Steve Benen notes another important point, i.e., that backing Toomey-Manchin shouldn’t even have been difficult in the first place: “proponents had bipartisan cover; the key provision was written by two conservatives; and the polls were entirely one-sided.”

Right, and I’d add two other things, one concerning Democrats, the other concerning Republicans. As Klein notes, we’re supposed to be giving Democrats points because they’ve embraced two of the three positions in our new political courage triumvirate. But as you may recall, the manner in which some of these red and swing state Dem Senators embraced gay marriage wasn’t at all impressive in the first place. A whole bunch of them stampeded forth in a very short time to support gay marriage, only because pending Supreme Court decisions gave them a rapidly shrinking window for getting on the right side of history on the issue. They did this well after many polls were already showing national majority support for marriage equality. (There are still three remaining holdouts.)

In the case of Republicans, significantly more of them are expected to embrace immigration reform than supported Manchin-Toomey. But of course, this is only happening because Republicans got slaughtered among Latinos in the last election, and know the party needs to repair relations with Latinos or flirt with demographic doom. It isn’t happening because Senators suddenly decided our broken immigration reform system has gotten so bad that the problem must be solved, so they’re ready to take a tough vote to fix it.

Meanwhile, on Manchin-Toomey, some of these Republican Senators who voted No really did appear to recognize that supporting it was the right thing to do. Some of them, such as Dean Heller, continue to say we need to improve our background check system, even while justifying the vote against Manchin-Toomey by citing bogus NRA “national gun registry” talking points that have been widely debunked by fact checkers and even Republicans like John McCain. Jeff Flake also continues to endorse the general policy goal of fixing background checks — even after voting No on Manchin-Toomey. So it looks as if Republican Senators will be willing to take a tough vote on a measure that will help the party (immigration reform) but were not willing to take a tough vote on one based on policy merits (Manchin-Toomey).

And so the argument that these Senators have already put themselves at an abundance of risk seems pretty thin.

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.