Senators Hillary Rodham Clinton and Barack Obama veered from collegial to clenched and combative in a debate on Thursday, with Mrs. Clinton turning especially aggressive as she all but accused Mr. Obama of plagiarism and derided his political message as “change you can Xerox.”
Mr. Obama, buoyed by 11 straight victories in the most recent nominating contests, sought to maintain a positive tone throughout, though at one point he accused Mrs. Clinton of suggesting that his supporters were “delusional” or “being duped” by his themes of hope and unity.
Those few sharp rejoinders, as well as an emotional closing comment by Mrs. Clinton that seemed to move the audience — and even Mr. Obama — were the most memorable moments in a debate that had been loaded with expectation, with Mrs. Clinton seeking to stop the Obama juggernaut.
After the 90 minute face-off was over, it was not clear that Mrs. Clinton, in the toughest position of the campaign for her, had done enough to change the course of the contest.
Mrs. Clinton, who is girding for March 4 Democratic primaries in Texas and Ohio that aides say she must win, alternated between high notes early in the debate — smiling and nodding at Mr. Obama, pitching her economic plans for the umpteenth time — and pointed criticisms that she has been making somewhat fruitlessly for weeks now, like portraying Mr. Obama as all talk and little action.
In her sharpest attack to date on the originality of his oratory and ideas, Mrs. Clinton cited news reports about Mr. Obama’s nearly verbatim use of remarks first delivered by a close ally, Gov. Deval Patrick of Massachusetts. She argued that Mr. Obama had drawn great praise for his speeches, and then questioned whether they had been plagiarized.
Playing off a trademark line of Mr. Obama’s, she said: “Lifting whole passages from someone else’s speeches is not change you can believe in. It’s change you can Xerox.”
The comment elicited loud groans and some applause from the audience at the University of Texas at Austin.
Mr. Obama softly spoke over her, saying, “Oh, but that’s not what happened there,” yet eventually chose not to engage, saying he wanted to reply only to her criticism on the issues. A moment earlier, though, he had defended his use of Mr. Patrick’s language, saying that it was limited to two lines — and that the criticisms reflected a “silly season in politics.”
“The notion that I had plagiarized from somebody who’s one of my national co-chairs who gave me the line and suggested that I use it, I think is silly,” he said to applause and laughter.
For the most part, the two rivals heaped their complaints and criticisms on Republicans — namely President Bush, whom the they mentioned a total of 23 times. By contrast, Mrs. Clinton mentioned the leading Republican presidential candidate, Senator John McCain of Arizona, twice; Mr. Obama mentioned him four times.
If the candidates spent the first 45 minutes acting more like running mates than rivals, Mrs. Clinton spent much of the last half of the debate trying to inflict damage on Mr. Obama.
At one point, she sought to undermine his stature by referring to an interview on MSNBC on Tuesday night, much replayed on cable news, in which a Texas official supporting Mr. Obama, State Senator Kirk Watson, could not cite a major legislative accomplishment of the candidate.
“I do think that words are important and words matter,” Mrs. Clinton said, “but actions speak louder than words, and I offer that.”
Defending his record in the Senate, Mr. Obama pushed back against Mrs. Clinton, suggesting that she was insulting the intelligence of the millions of people who had voted for him, attended his rallies and watched their debates.
“The implication is, is that, you know, the people who have been voting for me or involved in my campaign are somehow delusional,” Mr. Obama said to chuckles. “The thinking is that somehow they’re being duped and that eventually they’re going to see the reality of things.”
“Well,” he added, “I think they perceive reality of what’s going on in Washington very clearly.”
While Mrs. Clinton may have been harsher than Mr. Obama, she ended the debate with the night’s most memorable grace note, as if eager to leave voters with a gentle final impression after the political skirmishing.
“The hits I’ve taken in life are nothing compared to what goes on every single day in the lives of people across our country,” she said. “And I resolved at a very young age that I’d been blessed, and that I was called by my faith and by my upbringing to do what I could to give others the same opportunities and blessings that I took for granted.”
“You know, no matter what happens in this contest, I am honored to be here with Barack Obama. I am absolutely honored,” she said, reaching over to shake her rival’s hand. “You know, whatever happens, we’re going to be fine.”
Mrs. Clinton entered the debate with her advisers somewhat torn about how aggressive to be against Mr. Obama, who is enjoying significant political momentum after his string of victories and has a narrow lead in delegates for the Democratic nomination.
Some advisers said she believed that simply by sitting on a stage, making her cases side-by-side with Mr. Obama, would reap points because she would look experienced and presidential.
But others said she needed to be more assertive in making him seem ill-prepared for the job.
As for her actual performance, Mrs. Clinton appeared relaxed at times as she made her case. At other points, she looked as if she could not wait to deliver punches or respond to Mr. Obama’s remarks. Still, little that she said appeared to rattle him.
For much of the debate, the two candidates agreed over and over again: on their support for immigration reform, economic aid to struggling Americans and democracy in Cuba.
Each also tried to appeal to a major part of the Texas electorate, Hispanics, by emphasizing their support for immigration reform and their involvement in past legislation to help immigrants and their family members.
Mrs. Clinton has come to count on Hispanic voters, who helped her win nomination contests in Arizona, California, Nevada, and New Mexico, but Mr. Obama is hoping to make in-roads with populist economics arguments and by emphasizing the needs of immigrants.
Mrs. Clinton defended her support for building a physical barrier along the border with Mexico, noting twice that Mr. Obama voted for it as well, but at the same time she called for a review of the project, which, she said, had become “absurd” under the Bush administration.
“As with so much, the Bush administration has gone off the deep end, and they are unfortunately coming up with a plan that is counterproductive,” she said.
Mr. Obama almost entirely echoed her remarks, and also drew applause with his criticism of the current president. “The Bush administration is not good at listening; it’s not something they do well,” he said.
The candidates also agreed that no aspect of a bilingual culture had been bad for America.
“I think it’s important for a lot of Americans to do what I have never been able to do: learn another language,” Mrs. Clinton said. She noted that she opposed making English the official national language, but also said it should remain a “common unifying” language for all Americans.
Asked about Cuba, Mr. Obama said he was willing to meet with Raúl Castro “without preconditions,” but he also insisted that the talks would have to deal with human rights, releasing political prisoners and other issues.
Mrs. Clinton responded that the United States should have diplomatic negotiations “with anyone” but noted that she and Mr. Obama had differed on when and whether the president should offer a meeting with foreign leaders without preconditions.
“I would not meet with him until there was evidence that change is happening,” she said.
The candidates drew frequent applause as they made direct appeals to people in “Ohio and Texas,” a phrase they both used a few times.
Clinton advisers have said Mrs. Clinton must win the Texas and Ohio primaries by at least 10 percentage points if she has any hope of catching up with Mr. Obama in the delegate count, particularly because he has shown momentum recently at picking up support from elected officials who count as superdelegates.
The two candidates are set to meet for a final debate on Tuesday in Cleveland.