The Supreme Court is about to toss a judicial bomb into the middle of the presidential campaign, and nobody knows what impact it will have.
The bomb, of course, is the court's ruling on President Obama's healthcare law, which is expected next month.
At first glance, the political implications might look simple. If the court upholds the law, Obama's biggest legislative achievement, the president wins; if the court declares the law unconstitutional, he loses.
But as with many things in politics, it may not be that simple at all.
If the court upholds the law, Obama will hail the decision as proof that he was right all along.
But that won't change the unpleasant truth (for Obama) that the law is widely unpopular; polls show that more Americans want to scrap it than keep it. If Obama wins in the court, he'll have to spend precious campaign time defending a law that most of the electorate dislikes. That would be good news for his GOP rival, Mitt Romney.
Or take the contrary scenario: What happens if the court strikes down the law entirely?
At first glance, that would be a stinging defeat for the president; it would make him look like, well, a loser. Romney and other Republicans already have their talking points drafted: They'll say Obama should have been working on the economy but wasted time passing a law that turned out to be unconstitutional. And "unconstitutional" isn't a compliment.
"For most voters, 'unconstitutional' is synonymous with 'bad,'" Republican pollster Bill McInturff told me. "They're not going to look at it in a narrow legal sense."
But there's a contrarian view too: that a defeat in the court could turn into a political victory for Obama.
"It could be a great mobilizing event for liberals and Democrats," argues William A. Galston, a former aide to President Clinton. "A bitter loss mobilizes people in a way that success does not."
Democratic strategists have been working on their talking points too, and here's what they suggest Obama would say in the event of defeat: A Supreme Court dominated by conservative Republican appointees has deprived Americans of protections they liked, such as the guarantee that people with preexisting health conditions could still get insurance — and Romney's Republicans don't have anything to put in its place.
"It's a great argument to mobilize the base," Democratic pollster Celinda Lake said. "It would be great for turnout."
But there's a third, more complicated scenario: The court could uphold most of the law but strike down the "individual mandate," the federal requirement that everyone obtain health insurance or pay a fine.
Depending on what other provisions the court strikes down, the result could be chaos in policy land. If the court overturns the individual mandate but keeps the rule guaranteeing coverage to sick people, insurance companies will warn that their costs will go through the roof, and they might hike their rates to prove it. If the court overturns both the mandate and the insurance guarantee, the insurance companies will dodge that bullet, but Obama and Romney will be plunged into a furious debate over whether the truncated program that remains can be made workable.
It's not clear who would win that fight. In one sense, it would put Obama on friendly ground: Most of his healthcare plan would still be in place, but the part voters disliked most — the mandate — would be gone.
"The public will say, 'Phew.' They didn't think the mandate was essential," Lake predicted.
"The consequences of pulling the mandate out are not well understood," agreed McInturff. "It's going to be messy and hard to explain."
The Republican response, he predicted, would be that "Obamacare" without a mandate won't work, and they have a point: Without a mandate requiring healthy young people to purchase coverage, the economics of the president's plan don't quite pencil out.
But Republicans have a problem too. No one thinks the current system is working, but the GOP hasn't agreed on an alternative to put in Obamacare's place. Romney has promised to repeal and replace the president's law, but his current proposal is an unfinished framework. Republicans in Congress have nibbled around the issue, but they're nowhere near agreement on a full-scale alternative either.
And here's a wild card: Voters could resent any candidate who spends too much time talking about healthcare; that's not the issue that's at the top of their concerns.
"Voters want to hear the candidates tell them how they'd fix the economy," Republican pollster David Winston said. "They don't want to watch a rerun of the 2010 healthcare debate."
There's something to that. During the week the Supreme Court heard oral arguments, Obama's standing in the polls dropped a point or two, probably because news coverage was reminding voters about an issue most of them dislike.
About the only part of the public reaction that's predictable is this: Many voters will interpret the Supreme Court's actions as political, not as the product of dispassionate legal judgments. Big majorities, as high as 67%, have told pollsters they think the court's decision will be based on politics, not on the law.
One side or the other will gain an advantage from this fight, but at this point, it's still (and this is frustrating for this pundit) impossible to say which one.