Sen. John McCain further established himself as the clear front-runner in the GOP contests, despite a surprisingly strong showing by former Gov. Mike Huckabee. On the Democratic side, Sen. Barack Obama appeared to chip further away at the delegate tally and national lead of Sen. Hillary Clinton.
Neither party has officially tapped a nominee though McCain emerged, according to most analysts, as the man to beat.
"The Republican and Democratic presidential contests began diverging Tuesday, leaving the Democrats facing a long and potentially divisive nomination battle and the Republicans closer to an opportunity to put aside deep internal divisions and rally around a nominee," Adam Nagourney wrote in a news analysis for The New York Times.
The three leading Republican candidates fared well in different regions of the country. McCain's best showing was in the Northeast and along Route 66 from Illinois to California. Former Gov. Mitt Romney did well in his home state of Massachusetts as well as in Western states and among voters who identified themselves as conservatives. Huckabee, meanwhile, swept the South.
"Tonight, we've won a number of important victories in the closest thing we've had to a national primary," McCain said in his home state of Arizona with his family by his side. "We still have a ways to go, but we're much closer to the victory we've worked so hard to achieve."
On the NewsHour Tuesday night, syndicated columnist Mark Shields said McCain did two things in his speech.
"He was an antidote to the last debate where he was seen as mean spirited and occasionally churlish. He was very large and more magnanimous tonight, generous in his remarks about Mitt Romney, where there had been a very tough campaign," Shields said.
"The other thing is that he evoked humor, the story that mothers in Arizona -- because of the past failed candidacies of Barry Goldwater in 1964, Democrat Morris Udall in 1976 and Democrat Bruce Babbitt in 1988, as well as John McCain's own in 2000 -- was the only state where mothers didn't tell their children that they could grow up to be president of the United States, and John McCain said now maybe this time it might be different."
Huckabee used his speech as a platform to jumpstart his campaign, which has faltered since a surprise win in the Iowa caucuses.
"Today has been a day when the people have spoken, and today people across this county are saying 'Yes we heard what the pundits say, but this is our vote not theirs,' " Huckabee told supporters during a victory speech in Arkansas.
"Over the past few days a lot of people have been trying to say this is a two-man race. And you know what, it is! And we're in it!"
As more clarity appeared to emerge on the GOP side of the ledger, the Democratic race remained anything but clear as the delegate totals continued to trickle in from across the country.
What was definite was Illinois Sen. Barack Obama won more states than rival New York Sen. Hillary Clinton, but her campaign was headed toward a significant victory in California -- by far the nation's most populous state and the crown jewel of every national political race -- and her home state of New York.
"Because of party reforms in the past and a close race for delegates this year, a nightmare scenario is building for the Democratic National Convention in August: It is easy to imagine that Barack Obama could get to Denver with more pledged delegates than Hillary Clinton, but that she could get the nomination based on the votes of the super delegates," Politico reported.
Such an occurrence "would create havoc," a senior Obama aide warned in the same article.
The impact of Super Tuesday on the Democratic race will play out over the coming days and weeks as attention shifts to how the delegates will be divvied among them -- oftentimes under complicated rules that differ in each state.
"Before California and Missouri were counted, an analysis by The Associated Press based on incomplete vote totals showed that Mrs. Clinton had won 166 delegates and Mr. Obama had won 146 at stake Tuesday," the Times reported. "All told, Mrs. Clinton had 479 delegates and Mr. Obama had 386."
By swapping victories over the course of the night, neither Clinton nor Obama could declare a clear victory in speeches to supporters late Tuesday.
Speaking in New York, Clinton did not mention Obama, instead focusing her attention on her GOP rivals.
"After seven years of a president that listens only to the special interests, you're ready for a president that brings your voices, your values and your dreams to the White House. And tonight in record numbers you voted not just to re-make history but to re-make America," she said.
Obama looked to restate his case against Clinton as a member of the Washington establishment and reiterated his call for sweeping change to the political process.
"It's a choice between going into this election with Republicans and independents already united against us, or going against their nominee with a campaign that has united Americans of all parties, from all backgrounds, from all races, from all religions, around a common purpose," he said in speech to supporters in Chicago, according to the Washington Post.
Super Tuesday served as the first head-to-head test between Obama and Clinton after former North Carolina Sen. John Edwards dropped out of the race.
Black and young voters overwhelmingly supported Obama, while women went for Clinton by large margins, the Times reported. But white men -- who had largely voted for Edwards before -- appeared to be heading to Obama's camp after his departure from the race.
In exit polls conducted in California for the AP, Democrats and Republicans reported the economy was the most important issue facing the country, with about 90 percent of Democrats characterizing it as not so good or poor; about two-thirds of Republicans said the same.
On candidate qualities, McCain got strong support in exit polling from people valuing experience, leadership and the ability to beat Democrats in a general election. He was widely considered the best Republican to be commander in chief. Romney, for his part, dominated among people looking for a candidate who shared their values and those wanting a hard line against illegal immigrants.
For Romney, the loss in California is a particularly strong blow, as he had hoped a victory there could stop McCain's momentum.
"The Republican campaign is over," New York Times columnist David Brooks said on the NewsHour Tuesday night.
Romney also spent millions on television and radio ads in California after losing the Florida primary -- he was the only Republican candidate to air television ads in the state, according to the San Jose Mercury-News.
"McCain now looks to have the nomination, winning California. But the race has opened an ominous split in the party. Romney's hopes die with his California loss," wrote Carolyn Lochhead for the San Francisco Chronicle.
But for Romney's part, he pledged to fight on, saying "I think there are some people who thought it was all going to be done tonight. But it's not all done tonight. We're going to keep on battling. We're going to go all the way to the convention. We're going to win this thing, and we're going to get to the White House."
After the unprecedented number of contests on Tuesday, it's clear that the candidates have much more campaigning ahead of them. Four years ago, Massachusetts Sen. John Kerry locked up the Democratic nomination on March 2, the earliest date in recent memory.
Looking ahead, Louisiana and Washington state hold nominating contests this weekend for both parties while Republicans caucus in Kansas. Democrats also caucus in Nebraska and Maine. Next Tuesday, voters head to the polls in Maryland, Virginia and the District of Columbia for a "Potomac Primary."