"I've been trying to figure this out," says one House Republican of the current standoff over funding the government. "It seems to me that Boehner could do whatever he wants with Democrats on the floor and still get about 180 or 190 of us. So why doesn't he do that?"

The lawmaker was referring to the fact that a large majority of the House's 232 Republicans, plus a large majority of its 200 Democrats, would likely support a "clean" continuing resolution to fund the government but not defund, delay, or limit Obamacare. If House Speaker John Boehner were to bring such a bill to the floor, it would probably pass with a majority of Republican as well as Democratic votes. But Boehner doesn't do it.

If the Speaker did, he would raise the ire of the group of House GOP conservatives most committed to continuing the defund battle. There are various estimates of how many there are in that group -- probably about 30 core members, but perhaps 30, or even as many as 50, others who are sympathetic to the core position. Even so, a high estimate is about 80, meaning that even in the worst case scenario for a clean continuing resolution, Boehner would still have around 150 Republican votes to end the impasse. Given Democratic support, that would be more than enough.

But he doesn't do it. "I think the issue is, he's scared that those 30 people could somehow force a speaker's election," says the House Republican. "I don't know exactly, but clearly he thinks his speakership is a stake if he screws them."

So the standoff continues. But there are signs the terrain of battle has shifted so much that Obamacare -- the reason Republicans fought so hard over resolutions to fund the government in coming months -- is no longer the central issue in the fight.

As the shutdown took hold, the House GOP leadership changed course from trying to limit Obamacare to an effort to mitigate the effects of the shutdown. Boehner and his colleagues came up with bills that would fund the National Park Service, the Department of Veterans Affairs, the Smithsonian, the National Gallery of Art, the Holocaust Museum, and the District of Columbia government. The bills were considered under special rules, which in the end meant that House Democrats were able to kill them -- before Senate Democrats could kill them.

What distinguished the House agenda on Tuesday was that it wasn't about Obamacare. The parks bill, for example, did not contain a provision to defund or delay the president's national health care plan. The Smithsonian bill didn't either. And so on. One could argue that with the government shut down, Obamacare was effectively defunded, at least for the many days the government remains closed. But the fact is, on Tuesday the Republican focus shifted from going after Obamacare to trying to undo the most visible negative consequences of the shutdown.

Something similar was going on in the Senate. In a floor speech Tuesday, Republican Sen. Mike Lee, the originator of the defund-Obamacare drive, endorsed the idea of passing a number of narrowly-targeted government spending bills that have wide popular support and are "completely unrelated to Obamacare."

Lee acknowledged that Senate Majority Leader Harry Reid had killed earlier Republican attempts to reach an agreement and was likely to kill any future efforts. "So in light of that, let's leave Obamacare for another day," Lee said, "and not hold the vast majority of government functions hostage when the vast majority of government functions don't have anything to do with the implementation and enforcement of Obamacare."

A few hours later, in a conference call with conservative bloggers, Republican Sen. John Cornyn, who voted against the Mike Lee-Ted Cruz faction on the question of filibustering spending bills that contained Obamacare funding, sounded like he was ready to move on, too. "I think we are at an impasse on any Obamacare measure now, with the Democrats taking a very hard line," Cornyn said. "Any opportunity to defund Obamacare through the CR, if there was such an opportunity, is now goneā€¦.I agree with Mike that this is not the best vehicle or the right vehicle to fight that [Obamacare] fight."

Later Tuesday, Lee's office sought to reassure reporters that the senator was not abandoning the fight against Obamacare. "We are not backing off of defund in any way," said a spokesman. "We are trying to get Reid to agree to fund bills that don't touch Obamacare. 'Leave Obamacare for another day' could be TOMORROW if Reid agreed to pass our bills."

Still, there seemed little doubt that Lee was suggesting the GOP take a breather from Obamacare, and that was a significant step for the Senate's most determined advocate of defunding. It also reflected what was going on in the House, as Republicans turned their attention away from Obamacare and toward trying to ease the problems brought about by the shutdown.

Sometimes fights become so intense and so tangled that the original cause becomes obscured. In the government funding battle, the issue that sparked it all, Obamacare, was no longer center stage less than 24 hours after the shutdown began. The fight is now about the shutdown itself, and Obamacare has been pushed to the side.