CHICKASHA — Nine months ago, Barack Obama likened his Republican opposition to an illness. If he could just defeat Mitt Romney, Obama said, then the illness might subside. "I believe that if we're successful in this election -- when we're successful in this election -- that the fever may break," Obama told a fundraiser in Minneapolis last June.

After Obama won re-election, there was extensive discussion among his supporters about whether the Republican "fever" would, in fact, break. Would the fiscal cliff negotiations, which resulted in the GOP accepting a tax increase on the nation's highest earners, do the trick? If not, would coming fights over the debt ceiling and sequestration finally cure the Republican illness?

There was little speculation about whether something very different might happen: Would determined GOP opposition break Obama's fever? That is, could Republicans weaken the president's resolve to defeat the GOP and further raise taxes? That appears to be what has happened, at least for the moment. Republican determination to go through with sequestration, which Obama warned would have disastrous consequences nationwide, seems to have forced the president to change course.

At his March 1 news conference after meeting Republican leaders in the White House, Obama seemed resigned to the possibility that he cannot win the tax increases he seeks, and that after enlisting his entire administration in a campaign to frighten Americans about sequestration, the cuts have become a reality that he has to acknowledge.

"This is not going to be an apocalypse, I think, as some people have said," Obama declared (not mentioning that his administration had been behind most of the apocalypse talk). "It's just dumb. And it's going to hurt."

Nevertheless, Obama said that when the next budget fight happens, later in March over a resolution to fund the government for the rest of the fiscal year, he will accede to the reality of sequestration. "There's no reason," he said, "why we should have another crisis by shutting the government down in addition to these arbitrary spending cuts."

    Obama indicated that he still subscribes to a modified version of the "Republican fever" theory, expressing hope that the GOP might someday have a change of heart and go along with his proposals. But he clearly indicated that for the moment, he will move on to other things. "We can't let political gridlock around the budget stand in the way of other areas where we can make progress," Obama said, mentioning immigration, gun control, the minimum wage, and other issues he will pursue.

    To Republicans, Obama's words were a sign that a fever had broken -- and it wasn't the GOP's. "I definitely read a change in tone in that press conference," said one Senate aide. "Obama's tone has clearly shifted on the sequester. By using his press conference to call out those who've been predicting the apocalypse over the past few weeks, he was really calling out nobody more than himself. In that moment, I think, a lot of Republicans realized that the ground had shifted in this debate. The president overplayed his hand, and he knows it."

    "I thought the real news of the press conference was his admission that sequestration isn't the apocalypse," said another Senate aide. "And basically that the sky won't fall. If he doesn't direct his administration to pull the sky down (illegal immigrant releases, etc.) in the next few months, that will be a sign that his fever is breaking and he is ready to move on. Both Boehner and McConnell are adamant about not raising more taxes so hopefully he sees the writing on the wall."

    Some in the GOP saw public opinion at work. "The three-day Gallup tracking numbers certainly aren't good for him," said one House aide, pointing to surveys placing Obama's job approval rating at 47 percent approve versus 45 percent disapprove -- down from a post-election approval rating that topped out at 56 percent.

    Other Republicans saw Obama's move as a temporary change in tactics as the president continues the fight to raise taxes. But in the end, Republicans are welcoming the president's change in tone, even if it is just a temporary accommodation.

    Still, they don't see him changing his basic position on questions of spending and taxes, and they don't see any easier days ahead when Obama shifts from budget fights to his core second-term priorities. "Republicans need to understand that President Obama has no more intention of negotiating in good faith on immigration than he has on fiscal issues," said one last Senate aide. "His goal is to weaken the GOP so that he is in a better position to implement his agenda."

    (Byron York is chief political correspondent for The Washington Examiner.)