AUSTIN, Texas, March 5 -- Hillary Rodham Clinton elbowed her way to victories Tuesday in Ohio and Texas, snapping Barack Obama’s winning streak and resuscitating her flagging bid for the Democratic presidential nomination.

Addressing supporters in Columbus, Ohio, an exultant Clinton declared, “We’re just getting started.”

Obama, appearing disappointed, insisted the contest was still his to lose, citing his continuing edge in the delegate count. “We know this: No matter what happens tonight, we have nearly the same lead as we did this morning, and we are on our way to winning the nomination,” the Illinois senator told cheering fans at a late-night rally in San Antonio.

The Democrats split two other contests, Clinton winning handily in Rhode Island and Obama easily taking Vermont.

On the Republican side, John McCain swept the day’s four GOP primaries to clinch the Republican nomination and force Mike Huckabee from the race. He and the two Democrats called McCain to offer congratulations.

The Arizona senator, who staunchly supports the U.S. presence in Iraq, signaled his intention to make the war a major issue in the fall. “Our most vital security interests are involved there,” McCain told supporters in Dallas.

He planned a stop at the White House on Wednesday to receive the endorsement of President Bush, who beat McCain in his 2000 try for the White House. The two have had a tepid relationship ever since.

The Democratic race, by contrast, appears deeply unsettled after a long night of counting ballots in Ohio and Texas. The next major contest is April 22 in Pennsylvania, making for an unusually long stretch between races in this heavily compacted election season.

Wyoming will hold caucuses on Saturday, and Mississippi has a primary Tuesday. But neither is likely to reshape the essential dynamic of what has become the most competitive presidential nominating fight in at least 40 years. That promises at least another seven weeks of intensive campaigning.

Tuesday was the biggest day of balloting left on the Democrat’s election calendar--with 370 pledged delegates at stake in four contests--and voters responded as they have throughout the campaign, turning out in record numbers.

Obama had 1,443 delegates to Clinton’s 1,351, according to The Associated Press. It takes 2,025 to win the Democratic nomination.

Clinton picked up at least 75 delegates Tuesday and Obama gained at least 54, according to AP. Nearly 250 more remained to be awarded, including 67 in Texas caucuses. Those results were still undetermined early Wednesday morning.

Times staff writers Maria L. La Ganga, Scott Martelle, Maeve Reston, Louise Roug and Stuart Silverstein contributed to this report.