Austin, Texas ? Hillary Rodham Clinton accused presidential rival Barack Obama of political plagiarism Thursday night, but drew boos from a Democratic debate audience when she ridiculed him as the candidate of “change you can Xerox.”

Obama dismissed the charge out of hand, then turned the jeers to applause when he countered, “What we shouldn’t be doing is tearing each other down, we should be lifting the country up.”

The exchange marked an unusually pointed moment in an otherwise civil encounter in the days before March 4 primaries in Texas and Ohio – contests that even some of Clinton’s supporters say she must win to sustain her campaign for the White House.

The former first lady has lost 11 straight primaries and caucuses, and trails her rival in convention delegates. Obama has won a pair of big union endorsements in the past two days.

In a university auditorium in the heart of Texas, the two rivals agreed that high-tech surveillance measures are preferable to construction of a fence to curtail illegal immigration.

They disagreed on the proper response to a change in government in Cuba in the wake of Fidel Castro’s resignation. Clinton said she would refuse to sit down with incoming President Raul Castro until he implements political and economic reforms. Obama said he would meet “without preconditions,” but added that the U.S. agenda for such a session would include human rights in the Communist island nation.

Clinton was combative and complimentary by turns, and reflected on her well-known personal struggles in the debate’s final moments.

“Everyone here knows I’ve lived through some crises and some challenging moments in my life,” she said – a thinly veiled but clear reference to her husband’s affair with Monica Lewinsky and subsequent impeachment. But she added that nothing she had been through matched the everyday struggles of voters.

Then, offering unprompted praise to her rival, the one-time front-runner said, “No matter what happens in this contest, I am honored to be here with Barack Obama.”

Clinton largely sidestepped a question about so-called superdelegates, members of Congress, governors and party leaders who were not picked in primaries and caucuses. She said the issue would sort itself out, and “we’ll have a united Democratic party” for the fall campaign.

But Obama, who has won more primaries and caucuses said the contests must “count for something … that the will of the voters … is what ultimately will determine who our next nominee is going to be.”

Clinton went into the debate needing a change in the course of the campaign, and waited patiently for an opening to try to diminish her rival, seated inches away on the stage. “I think you can tell from the first 45 minutes Senator Obama and I have a lot in common,” she said.

Barely pausing for breath, she went on to say there were differences.

First, she said she had seen a supporter of Obama interviewed on television recently, and unable to name a single accomplishment the Illinois senator had on his record.

“Words are important and words matter but actions speak louder than words,” she said.

Obama agreed with that, then noted that Clinton lately had been urging voters to turn against him by saying, “let’s get real.”

“And the implication is that the people who’ve been voting for me or are involved in my campaign are somehow delusional,” Obama said.

Clinton also raised Obama’s use in his campaign speeches of words first uttered by his friend, Massachusetts Gov. Deval Patrick.

“If your candidacy is going to be about words, then they should be your own words,” she said. “… Lifting whole passages from someone else’s speeches is not change you can believe in, it’s change you can Xerox.”

The debate audience booed.

Obama said the entire controversy was evidence of a “silly season” that the public finds dispiriting. Besides, he said of his speeches at one point, “I’ve got to admit, some of them are pretty good.”