After vowing to kill President Obama's eponymous health-care law for going on four years now, Republicans appear to finally be moving on.

To be sure, the party hasn't dropped its opposition to ObamaCare. But a shift in the way it has framed that opposition indicates that the days of "repeal or bust" are a thing of the past.

Speaker of the House John Boehner (R-Ohio) said Thursday that coming up with an ObamaCare alternative would be "one of the big issues" at the GOP's annual policy conference this month, adding that such a proposal could come up for a vote this year.

"It's important for us as a party, especially in an election year, to tell the people what you're for," he said. "We're for getting rid of ObamaCare and replacing it with a patient-centered health-care system."

It's a subtle shift, but a significant one.

The GOP-led House has voted 47 times to repeal ObamaCare. And just last October, the party shut down the federal government in a last-ditch gambit to nix the law, without offering any sound alternative. True, Republicans have thrown out a few legislative options of their own, but those ideas are generally considered unworkable, and none have gained consensus support.

In that light, simply saying that an official GOP alternative is on the way is a big step away from the nihilistic rhetoric of the past.

Meanwhile, congressional Republicans of all stripes indicate they won't use the coming debt-ceiling negotiations to bargain over ObamaCare. Sure, Sen. Ted Cruz (R-Texas) may still be in favor of doing whatever it takes to kill the law, but his peers are reportedly urging him to give it up already.

Outside Congress, GOP-aligned groups are similarly scaling back their opposition. As Red State's Erick Erickson notes, groups like the Business Roundtable and Chamber of Commerce have accepted, to varying degrees, that ObamaCare is here to stay. And the party itself, after being attacked by conservative boosters for dropping the defund tactic last year, has started to fight back against its critics on the Right — remember Boehner accusing such groups of having "lost all credibility"?

Here's Erickson:

The lobbying groups who have open access to Republican leaders are abandoning repeal. The wonks the GOP leaders listen to are abandoning repeal. The outside groups the GOP leaders work with have begun attacking conservative candidates. The outside groups who help conservatives are being shut out by the party.

They are laying the groundwork to bail on fighting ObamaCare. [Red State]

So what changed?

Simply put, ObamaCare went into effect, and it hasn't entered the dreaded death spiral or set the Constitution on fire. In fact, it's starting to gain strength and popularity.

Republicans conceded last year that it would be much harder to stop ObamaCare once the health-care exchanges opened in October, and even harder still once people started receiving their new health care in January. That's why they considered the defund gambit so important. As Cruz put it, October was their last hope of preventing ObamaCare from becoming a "permanent feature of the American economy."

Now that ObamaCare coverage has kicked in, repealing it would mean stripping people — many of whom either just enrolled in less expensive plans or obtained coverage for the first time — of their new insurance.

"It's no longer just a piece of paper that you can repeal and it goes away," Sen. Ron Johnson (R-Wis.) told The New York Times this month. "There's something there. We have to recognize that reality. We have to deal with the people that are currently covered under ObamaCare."

We've seen this coming for some time. Hoping to turn ObamaCare opposition into a winning 2014 argument, Republicans have insisted that the law will prove to be an unmitigated disaster. Now that the law is proving relatively successful — though not entirely problem-free — they don't really have a choice but to come up with a true alternative.