Hotline On Call

"His signature legislative achievement is found unconstitutional? I'd say that's a setback," one Republican insider said.

"[It] would enflame the left against the high court but confirm for everyone else the recklessness and lack of judgment that went into the president's manic push for the legislation," another said.

Other Republican insiders were less enthusiastic. "We get to say 'I told you so,' but we lose a major issue for the fall," one said.

Some warned that the GOP should not rely on the Supreme Court decision alone. The health care issue continues to loom large in the mind of voters, they say, and the problem is far from fixed.

"Win this one and everyone will see the emperor has no clothes," a GOP insider said. "But the GOP needs a positive plan on health care-- this issue isn't going away."

Another chimed in: "If we are smart it will be a defeat of for Democrats and we won't take credit or dance on the grave, but instead will have an immediate alternative--if we are smart."

Still, others warned that the Democrats could spin this into a positive for their party. "Republicans will have proven their point, but the President can start campaigning on the issue all over again," one said. "There is still a demand for health care reform among the voters."

Democratic agreed a negative Supreme Court decision would hurt their party, although they were less dire about the consequences. Thirty-four percent of them said it would be a big win for the GOP, while 31 percent said it would be a small victory.

"If the Court strikes the entire law, it will invalidate signature achievement of the Obama Administration," one Democratic insider said. "It may incite a backlash among supporters but that will not be enough to make up for the loss of the law."

Another agreed: "There's nothing like, 'It's unconstitutional,' for a talking point."

Others, however, were hopeful that the law being invalidated would fire up the base and give the Obama administration something to talk about.

"It will galvanize the Democratic base to run against the Republican court and Republican congress," one Democratic insider said. Another summed up: "Democrats will win if Republicans take away health care from Americans."

Some hoped with the health care debate re-set, Democrats would do a better job of owning the issue and the conversation this time around.

"It all depends on the spin," one Democratic insider said. "I hope the administration does better with a do-over."

Whether the nation's highest court rules the law unconstitutional remains unclear. What is certain, however, is the issue will loom large as voters decide to give Obama a second term. And that could make things complicated for the likely GOP nominee, former Massachusetts Gov. Mitt Romney.

National Journal Insiders, including some Republicans, are deeply skeptical the GOP presidential front-runner can attack the president over the health care law. As governor of Massachusetts, Romney backed health care reform that served as a template for Obama's signature legislative accomplishment, raising the possibility that any attack he levels will be seen as hypocritical.

Ninety-five percent of Democrats said Romney's criticism of the national health care law will be either ineffective or very ineffective. As one insider put it, "He practically wrote the darn thing!"

The most glaring similarity between Romney's and Obama's health care laws is the individual mandate, a provision that polls poorly among voters. Romney has argued his mandate, because it's confined to a single state, is different than the national version, but insiders say that argument won't satisfy voters.

It's "hard for Romney to argue that state mandates are fine but federal mandates are not," one said. "More doublespeak from a flip-flopping phony."

"Since 90 percent of the Republican attack is based on the mandate, not a lot of daylight for Romney," another added.

For the most part, Republicans are more bullish about Romney's prospects. More than 60 percent of them contend the former governor can effectively use Obama's law effectively or very effectively, arguing he at least attempted to fix a problem that many voters care deeply about.

"Mitt can credibly say he is one of only a few Republicans to try to fix health care insurance problem, and that at least his solution, while imperfect, was constitutional, whereas the solution offered by the former constitutional law professor was not," one GOP insider said.

"Look voters care about health care. A lot," another added. "And Romney can at least argues he cares about it, too."

But even some in the GOP are skeptical Romney can attack Obama over health care - 37 percent of them said he the issue would be ineffective in his hands.

"Even by the most forgivable standards, Mitt doesn't have a PowerPoint to explain his MassCare fiasco," one Republican said. "Ted Kennedy's having a laugh somewhere."

A second Republican added, "Him pretending the law in Massachusetts is so very different than Obamacare is just fiction and plays into him being inauthentic. Not wonderful."