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.

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.

Rick Santorum won two Southern state GOP presidential primaries Tuesday, embarrassing 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.

Texas Congressman Ron Paul hasn't won any of the 23 Republican presidential primaries or caucuses already in the 2012 history books.

He's captured only 29 delegates, just five percent of those awarded in contests to date. (Frontrunner Mitt Romney has 340 committed delegates, 58 percent of those officially allotted, according to NPR calculations.)

A next-day analysis of the Republican presidential primaries in Michigan and Arizona won by Mitt Romney underscores one of his weaknesses with his party's base, especially with the ascent of his now-chief rival Rick Santorum: he fares more poorly with born-again and evangelical voters than with non-evangelicals.

Republican presidential candidate Mitt Romney told a reporter Wednesday that he opposes a measure being considered by the Senate that would allow employers to decline to provide contraception coverage to women.

"I'm not for the bill," Romney said during an interview with Ohio News Network reporter Jim Heath. "But, look, the idea of presidential candidates getting into questions about contraception within a relationship between a man and a woman, husband and wife, I'm not going there."

Former Massachusetts Gov. Mitt Romney notched two big wins Tuesday, upping his Republican presidential delegate count and taking modest-plus momentum into the week leading up to Super Tuesday on March 6.

With the Michigan and Arizona primaries in the history books as Romney's fifth and sixth victories, we're looking ahead to Super Tuesday, when presidential contests will be held in 10 states and 413 delegates will be up for grabs.