Liz Halloran

President Obama is leading presumed GOP nominee Mitt Romney big in recent national polls.

No, wait. Polls show he's trailing Romney by a couple of percentage points.

Oh — this just in: Obama is actually leading Romney, but the race is tightening.

It's a general election poll-a-palooza out there, people.

But what do all the numbers mean?

"I have friends who support Obama, and friends who support Mitt Romney," says Scott Keeter, survey research director at Pew Research Center. "I tell them not to get too excited or too depressed at this point."

After going 0-for-3 in Tuesday's presidential primaries, a defiant Rick Santorum dismissed calls to drop out and predicted he'll win the next contest in his home state of Pennsylvania on April 24.

He'll have to — and not because it would put the former Pennsylvania senator on a path to defeat front-runner Mitt Romney, who has been racking up delegates and is increasingly seen as the inevitable nominee.

A loss in Pennsylvania, where recent polls show Santorum is weakening, would "destroy the rationale for him continuing," says Pennsylvania pollster G. Terry Madonna.

Voters in Wisconsin's GOP primary Tuesday are poised to help former Massachusetts Gov. Mitt Romney wrap up his dogged, well-financed quest for the Republican presidential nomination.

But the winner-take-all primary and Romney's drawn-out battle with former Pennsylvania Sen. Rick Santorum have been overshadowed by the campaign to recall GOP Gov. Scott Walker, whose anti-union efforts since his 2010 election have cleaved the Badger State.

On the final morning of its three-day health care law extravaganza, the U.S. Supreme Court wrestled with the question of whether parts of the 2010 federal statute can survive if the justices strike down its central tenet: the individual insurance requirement.

In other words, if the nine justices find the insurance mandate unconstitutional when they rule by June, would that mean that the entire law also fails the constitutionality test?

A clearly divided U.S. Supreme Court on Tuesday took up the centerpiece of President Obama's health care law: its requirement that by 2014 individuals have insurance coverage or face a penalty.

In contrast to Monday's dense and technical arguments, Tuesday's session was filled with sharp rhetorical volleys and clever analogies. Here are some of the more telling exchanges between the lawyers and the high court justices.

The U.S. Supreme Court on Monday opened three days of oral arguments over the constitutionality of the insurance requirement embedded in President Obama's landmark health care law with a simple question and an obscure 1867 law.

The question: Does the court even have the right to hear the health care challenge, given that the Anti-Injunction Act prevents federal courts from taking cases where taxpayers are trying to prevent the government from "assessing or collecting" taxes?

The U.S. Supreme Court is set to begin hearing oral arguments Monday in a Republican-led challenge to the national health care law that has convulsed the country and its political class for more than two years — and may well define President Obama's tenure in the White House.

Mary Beth Kopidlansky of Waukesha says she knows who she'll vote for in Wisconsin's upcoming GOP presidential primary (Mitt Romney), but that's not really what she's interested in talking about.

For Kopidlansky, and most potential voters in this most Republican of Wisconsin counties, the contest that is consuming them and the rest of the state is not the state's April 3 presidential primary when 42 potentially crucial delegates will be awarded.

Rick Santorum won two Southern state GOP presidential primaries Tuesday, embarassing Mitt Romney who had predicted he'd take one.

Second-place finisher Newt Gingrich vowed to fight on to Tampa, tag teaming Romney along with Santorum. The "three-way dynamic," as he put it, is a winner for Gingrich and, perhaps, his dream of deal-making at the convention, and for Romney, too, whose Southern result could have been much worse if he'd been posting up against Santorum alone.

Mitt Romney's stilted efforts to relate to Dixie voters by tossing off a few "y'alls" and references to grits have been roundly mocked as awkward pandering.

And rightfully so, says political scientist Marvin King, who cringed at the GOP candidate's sprinkling of vernacular and Southern stereotypes into his patter during appearances in Mississippi and Alabama. The two states hold their Republican presidential primaries Tuesday.

"You can tell Romney wasn't expecting to campaign down here, and it shows," says King of the University of Mississippi.