WASHINGTON (AP) — Hillary Rodham Clinton, fresh off a campaign-saving comeback, hinted Wednesday at the possibility of sharing the Democratic presidential ticket with Barack Obama – with her at the top. Obama played down his losses, stressing that he still holds the lead in number of delegates.

On a night that failed to clarify the Democratic race, John McCain Tuesday clinched the Republican nomination. Clinton won primaries in Texas, Ohio and Rhode Island, halting Obama's winning streak. Obama won in Vermont.

Both Democrats insisted on Wednesday they had the best credentials to go head to head – or as Clinton put it "toe to toe" – against McCain.

Asked on CBS's "The Early Show" whether she and Obama should be on the same ticket, Clinton said:

"That may be where this is headed, but of course we have to decide who is on the top of ticket. I think the people of Ohio very clearly said that it should be me."

Obama, who had hoped to knock Clinton out of the race on Tuesday, said he would prevail despite facing a tenacious candidate who "just keeps on ticking." Clinton acknowledged the race was close and said it would come down to her credentials on national security and the economy.

The two presidential contenders made the rounds of the morning network television news shows Wednesday, declaring only one thing certain – that the campaign would go on and that the next big showdown would occur April 22 in Pennsylvania.

McCain, whose grasp on the nomination once seemed a distant reach, was headed for the White House Wednesday to have lunch with President Bush and get his endorsement. Bitter rivals in the 2000 presidential primaries, the two have forged an uneasy relationship during Bush's administration and have clashed on issues such as campaign finance, tax cuts, global warming and defining torture.

Despite Clinton's victories Tuesday night, Obama came away with a large share of delegates, too, in counting that continued Wednesday.

"We still have an insurmountable lead," Obama said.

Clinton and Obama spent most of the past two weeks in Ohio and Texas in a bruising campaign, with the former first lady questioning his sincerity in opposing the North American Free Trade Agreement and darkly hinting he's not ready to be commander in chief in a crisis.

Based on their current delegate counts, neither candidate can win enough delegates in the remaining primaries and caucuses to secure the nomination without the help of nearly 800 party officials and top elected officials who also have a voice in the selection. On Wednesday, Clinton and her campaign clearly aimed their case at those so-called "superdelegates" – a strategy that could take the nomination fight all the way to the party's August national convention in Denver.

"New questions are being raised, new challenges are being put to my opponent," she said. "Superdelegates are supposed to take all that information on board and they are supposed to be exercising the judgment that people would have exercised if this information and challenges had been available several months ago."

She said voters are being drawn to her argument that she would be the better commander in chief, the best steward of the economy and that she can better confront McCain in the general election.

Obama countered that on a key national security issue – the war in Iraq – "she got it wrong" by supporting Bush's call for authority to use of force.

As for superdelegates, Obama said he expected them to rally around him.

"I don't think it will necessarily go to the convention floor," he told reporters aboard his plane before taking off from San Antonio for Chicago.

He also said he will challenge Clinton on her foreign policy credentials.

"Was she negotiating treaties? Was she handling crises? The answer is no," he said. "She made a series of arguments on why she should be a superior candidate. I think it's important to examine that argument."

In Tuesday's four-state competition for delegates, Clinton picked up at least 115, to at least 88 for Obama. Nearly 170 more remained to be allocated for the night, 154 of them in the Texas primary and the caucuses that immediately followed.

Obama had a lead in Texas caucuses before counting closed for the night Tuesday, to be resumed Wednesday.

Obama had a total of 1,477 delegates, including separately chosen party and elected officials known as superdelegates, according to the Associated Press count. He picked up three superdelegate endorsements Tuesday.

Clinton had 1,391 delegates. It takes 2,025 to win the nomination.

The count does not include delegates from Florida and Michigan, who were penalized by the Democratic Party for moving up their primaries ahead of a schedule set by the Democratic National Committee. None of the Democratic candidates campaigned in either state. But Clinton, who won the popular vote in both state primaries, on Wednesday renewed her call for Florida and Michigan to be counted in the nomination race.

"It's a mistake for the Democratic Party to punish these two states," she said. "I don't see how a Democratic nominee goes forward alienating two of the most important states."

McCain surpassed the 1,191 delegates needed to win his party's nomination against odds that seemed steep only a few months ago, and all but impossible last summer.

Facing a couple of well-financed marquee candidates in a crowded field, the Arizona senator opened his comeback in New Hampshire's leadoff primary, rolled over Rudy Giuliani in Florida and finished off Mitt Romney after Super Tuesday on Feb. 5.

Mike Huckabee hung in until Tuesday night, gamely keeping up the fight weeks after dropping from long shot to afterthought.

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Associated Press Writer Tom Raum in San Antonio contributed to this report.