Why couldn’t President Obama get expanded background checks through the Senate, given that the idea is supported by over eight in 10 Americans? The chatter around that question continues this morning, with the New York Times weighing in with a big piece arguing that the failure of the Toomey-Manchin compromise in the Senate is rooted in Obama’s unwillingness to “twist arms.”

The Times piece, which comes after Maureen Dowd made a similar argument over the weekend, traffics heavily in what a lot of folks like to describe as the Green Lantern Theory of Presidential Power. The thesis appears to be that Toomey-Manchin failed because Obama failed to put enough pressure on red state Democratic Senators like Mark Begich, and that this bodes ill for the rest of his presidency.

“Mr. Begich’s defiance and that of other Democrats who voted against Mr. Obama appear to have come with little cost,” the Times reports. “After more than four years in the Oval Office, the president has rarely demonstrated an appetite for ruthless politics that instills fear in lawmakers.”

But this thesis suffers from several problems. To begin with, even if every red state Democrat had voted for the measure, it still wouldn’t have passed.

Just look at the roll call for the vote. It failed by 54-46; if Harry Reid had not voted against the measure for procedural reasons, the tally would have been 55-45. Four red state Dems voted against the bill: Begich, Heidi Heitkamp, Mark Pryor and Max Baucus.

In other words, if Obama had twisted the arms of every one of those Democrats into pretzels — indeed, if he had twisted all of their arms together into one giant tangle and mounted it atop the Capitol — it still wouldn’t have achieved the 60 votes necessary to pass.

What about the gettable Republicans who voted against the bill, such as Dean Heller and Jeff Flake? The Times story has little to say about the role Republicans played in killing the measure, but it’s hard to see how arm twisting from a Democratic president would have won them over. The simple fact, as Steve Benen aptly demonstrated in chart form the other day, is that the proposal failed because virtually every Republican Senator voted against it. The GOP — and the 60 vote Senate – killed Manchin-Toomey. The Times piece doesn’t mention that 60 vote thing, either.

Now, if a few more Republicans had backed the proposal – meaning it would have passed if those red state Dems were to vote Yes — it would have been fair to ask whether Obama was doing enough to win them over.  But even here it’s unclear how effective more presidential pressure on these Dems would have been. If they were basing their vote in the calculation that they need to achieve distance from the president and signal cultural affinity with their red state constituents, as many have speculated, any open pressure would only make the vote harder for them.

What about behind-the-scenes arms twisting? I’m highly skeptical this would have made a difference in this scenario, either. Plainly, these Senators had calculated that this vote was extraordinarily difficult for them politically. After all, private pressure on them from the families — which various reports described as very intense — wasn’t enough to move them.

I will make one concession to the “arm twisting” theory of the case. If on the off chance the proposal comes up for a vote again, and a few more Republicans appear more gettable, Obama should indeed push red state Dems very hard to vote for it. I doubt that would matter much; in this scenario it would be more likely that they would support it of their own accord, because — unlike this time — they would be in the position of deciding whether it passed or failed. But, sure, if all this happens, by all means, try more arm twisting.

At any rate, all of this is a counter factual and speculative to begin with. The simple truth is that the Republican Party — and the 60 vote Senate — are the prime culprits in the killing of Toomey-Manchin. No amount of Green Lantern theorizing can obscure what happened here.

* Where did the Tsarnaev brothers get their guns? A key nugget from the Post’s write-up of the investigation:

Authorities are trying to trace a handgun recovered from the suspects. Law enforcement sources said the effort has been delayed because the serial number was removed. Technicians are working to determine the numbers, after which the weapons will be traced by a Bureau of Alcohol, Tobacco, Firearms and Explosives facility in West Virginia.

CNN reported yesterday that investigators believe the guns came from “elsewhere,” but it remains unclear what that means.

* Tsarnaev says brothers acted alone: From the New York Times overview of the questioning of Dzhokhar Tsarnaev: “He said that he knew of no other plots and that he and his brother had acted alone, and he said he knew of no more bombs that had not been detonated.”

If this bears out — and there continues to be no evidence of ties to Al Qaeda – the criticism of the administration for not holding Tsarnaev as an “enemy combatant” will be even tougher to sustain.

 * Republicans plan to probe the bombings: House Republicans are planning a major investigation into whether the FBI botched its initial investigation into Tamerlan Tsarnaev, which was done at the request of the Russian government. The big question is whether sustained attention to this will complicate the debate over immigration reform, and if so, how.

* Rand Paul flubs the Boston bombings: Glenn Kessler has a good piece taking apart Senator Paul’s suggestion that the system “allowed two individuals to immigrate to the United States from the Chechen Republican in Russia, an area known as a hotbed of Islamic extremism, who then committed acts of terrorism.” Conclusion:

Paul appears to suggest that U.S. immigration officials, in granting an asylum petition from the father, could have discerned that two minor children, after living in the United States for a decade, would eventually commit a terrorist act. That would require an extraordinary amount of clairvoyance. In any case, the key question for immigration officials was the asylum case made by their father; the minor children had nothing to do with it.

As noted here yesterday, there are legitimate ways to discuss the Boston bombings in the context of the debate over immigration reform, but this from Paul is just garbage.

* The bombings as 2016 issue for the right? Speculating on Rand Paul’s move above, the First Read crew (no link yet) makes an intriguing point:

You can’t help but wonder if Paul is seizing a potential opportunity to be to the right of potential 2016 foes on this issue.

And so the bombing could now enter into 2016 GOP primary politics.

* Why Tsarnaev should be tried in civilian courts: The Post’s editorial this morning gets at another reason why the “enemy combatant” talk is so misguided: Because it is essential that

the United States is seen by the world as capable of responding to a serious terrorist attack under the rule of law. The Bush administration’s failure to respect the Geneva Conventions and the U.N. Convention against Torture following the attacks of Sept. 11, 2001, not only gravely damaged U.S. prestige but also gave autocrats around the world an excuse to flout human rights standards in their own pursuit of “terrorism,” real or concocted.

* And flight delays kick in big time: The sequester cuts are now leading to serious delays in flight takeoffs for the second straight day, which is likely to provoke another round of finger-pointing over who is to blame for them. It’s unclear whether Republicans intend to continue claiming the sequester is a “victory” for them while blaming Obama for its actual impact.

What else?

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