A tense Democratic race heads to Pa.

— -- Democratic presidential contender Hillary Clinton rejuvenated her flagging campaign and broke rival Barack Obama's long winning streak Tuesday with victories in the Ohio and Texas primaries. The results mean that their nomination battle will continue at least to the next big primary in Pennsylvania next month — and perhaps longer.

Meanwhile, Arizona Sen. John McCain clinched the Republican nomination with a sweep of primaries in Ohio, Texas, Rhode Island and Vermont.

He was scheduled to visit the White House today for a Rose Garden endorsement by President Bush. Former Arkansas governor Mike Huckabee, calling his GOP campaign "the journey of a lifetime," dropped his challenge late Tuesday and pledged to work for McCain's election in the fall.

The Democrats split the smaller states: Obama carried Vermont; Clinton won in Rhode Island.

The night's focus was on the bigger states, which had a trove of 334 delegates at stake.

"People of Ohio have said it loudly and clearly," Clinton told cheering supporters in Columbus after claiming victory in Ohio. "We're going on, we're going strong, and we're going all the way."

A few minutes later, before the results in Texas were clear, Obama emerged to tell his own spirited crowd in San Antonio: "No matter what happens tonight, we have nearly the same delegate lead that we had this morning, and we are on our way to winning this nomination."

He added, "Si, se puede," Spanish for his campaign slogan, "Yes, we can!"

Obama had hoped after winning 11 straight contests that victories in Ohio and Texas might provide a knockout punch, persuading Clinton to end her campaign and clearing his path to a historical nomination at the party's August convention in Denver.

With Clinton's comeback, however, Tuesday became a political Groundhog Day for the Democratic contenders, an outcome that signaled six more weeks of campaigning — or, to be precise, seven more weeks until the April 22 Pennsylvania's primary, the biggest delegate prize left on the horizon.

Clinton managed to curtail Obama's charge after two months of roller coaster contests: Obama's stunning victory in Iowa, Clinton's unexpected rebound in New Hampshire, Obama's show of strength in South Carolina, the divided results in the "Super Tuesday" contests on Feb. 5 and Obama's winning streak since then.

It's not clear that either candidate could end the primary season with enough pledged delegates to clinch the nomination; 2,025 are needed. The decisions of party officials known as "super delegates" may prove to be decisive.

Surveys of voters as they left polling places in Texas and Ohio showed more than six in 10 saying the "super delegates" should vote based on the results of their states' primaries and caucuses, but they aren't obliged to do so and can change their minds if they wish.

The exit polls indicated indicated that Clinton won by regaining support from the classic Democratic voters who initially boosted her campaign: white women, less-educated Americans and seniors.

Obama held on to his core support groups, too, including blacks, young people and more affluent and better-educated Americans.