Blame for the government shutdown, now in day two, has winnowed to fewer and fewer people. First it was House Republicans, then it was Tea Party membership, then just the party's leaders. Now the blame may come down to two people: the bitter interpersonal feud between Harry Reid and John Boehner.

On Tuesday, we noted the immediate manifestation of that feud, when Reid's office leaked emails to Politico showing that Boehner worked behind the scenes to protect the same health care subsidy for congressional staff that he excoriated from the House floor on Monday. (As noted by Paul Kane, Reid's chief of staff admitted the leak.) Of course Boehner tried to protect it; the amendment to kill the subsidy that Boehner was advocating has been roundly disparaged, and any boss worth his salt would fight to protect his staff. Boehner's floor speech, too, was politically necessary: He needed to step up for the caucus he leads. But the hypocrisy of the speech became obvious in the aftermath of the leak, wounding Boehner exactly as Reid's chief of staff, David Krone, anticipated. (Also read The Washington Post's Erik Wemple on how the amendment fight was sort of Politico's fault anyway.)

In a long string of tweets Tuesday evening, The National Review's Robert Costa, who has emerged as the preeminent reporter on the Republican Party's budget back-and-forth, explained how the tension between those two offices is ensuring that the shutdown likely won't be resolved any time soon.

Costa also points to a January Atlantic Wire article noting that the tension between the two offices predates this current budget battle. "According to 'multiple sources,'" that story read, "Boehner pointed his finger at Reid and without any other fanfare said, 'Go fuck yourself.'" That tension simmered over the course of the year, particularly once Boehner pledged to allow his caucus more procedural flexibility in drafting and responding to legislation. The end result? A shut-down government in which Democrats decry Boehner from the floor, an unusually aggressive move in a building that prides itself on musty rules like not calling people out by name. On Monday, for example, Rep. Chris Van Hollen of Maryland suggested that Boehner hand his gavel to Sen. Ted Cruz, since Cruz is now apparently calling the shots.

Both leaders, however uneager to do so, are under pressure to resolve the dispute. But it's clear that Boehner is under more pressure — from his opposition, from the media, and from his own party. The Republicans clearly bear the blame for what's happening in Washington, as articulated by both The Washington Post and The New York Times editorial pages on Wednesday. The Post writes that "Republican leaders of the House of Representatives are failing," and should "fulfill their basic duties … or make way for legislators who will." The Times calls it "John Boehner's Shutdown," noting that "at any point" he could bring an unamended funding resolution to the floor of the House where it would be passed by Democrats and a growing contingent of vocal House Republicans.

He won't, Costa predicts, at least not over the short- or medium-term. In an interview with the Post's Ezra Klein, Costa explained the politics at play. "[H]e may have the votes on paper," Costa suggests. "But he'd create chaos. It'd be like fiscal cliff level chaos." As others have in the past, Costa points the finger in part at the elimination of earmarks, the riders to legislation that allowed legislators to include funding for projects in their districts. When that practice was eliminated — renewed by Boehner last year — it made the politics of cobbling together votes trickier. It used to be that congressional leadership could secure votes for controversial bills by allowing wavering legislators to bring something back to their constituents. This was derided as pork, but generally served the need of representatives and their districts. Without that enticement, legislators are more susceptible to those who can rally their constituents on specific issues — like Obamacare. Gotta keep the voters happy.

And Boehner has to keep his members happy, particularly if he wants to remain speaker. (Democrats have half-jokingly suggested they'd support his next bid if he brings an unamended funding bill — a clean continuing resolution or CR — forward.) Costa explained his perception of Boehner's strategy at this point in a post late Tuesday.

Based on my latest conversations with insiders, their plan isn’t to eventually whip Republicans toward a clean CR and back down after a few days of messaging the shutdown, as some have believed; it’s to keep fighting, and, in the process, preserve the House GOP’s fragile unity — and maybe, if they’re lucky, win a concession from Senate majority leader Harry Reid.

Echoing a point we made on Tuesday, Costa explained the long game in response to a question-and-answer at Reddit.com.

Remember, the defund/repeal efforts aren't only about actually killing the law or even bringing Obama to the table, but about messaging ahead of the 2014 midterms. Republicans are already planning to, once again, run against Obamacare and these campaigns against the law are part of setting up that argument. The shutdown, in a sense, is the ultimate messaging opportunity, since it coincides with the beginning of Obamacare's implementation, when Republicans are trying to make a broad case about federal dysfunction and bureaucracy.

That has particular significance for Republicans in the Senate, where they're poised to regain the majority. Boehner is willing to absorb the heat now if he thinks that he can better position Republican Senate candidates next year. After all, what better way to defeat the loathed Harry Reid than to kick him out of power?

Update, 1:00 p.m.: An olive branch, as Reid sends Boehner a letter articulating his argument in more friendly terms.

In case it wasn't already obvious, you should follow Robert Costa on Twitter if you're interested in staying up to date on the shutdown fight.