Hillary Rodham Clinton accused Democratic presidential rival Barack Obama of political plagiarism Thursday night and said he represented "change you can Xerox."
Obama dismissed the charge out of hand, adding in a campaign debate, "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.
In a university auditorium in the heart of Texas, the two 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 the U.S. agenda for such a session would include human rights in the communist island nation.
They also sparred frequently about health care, a bedrock issue of the campaign.
Clinton said repeatedly that Obama's plan would leave 15 million Americans uncovered.
But he, in turn, accused the former first lady of mishandling the issue by working in secrecy when her husband was in the White House.
"I'm going to do things differently," he said. "We can have great plans, but if we don't change how the politics is working in Washington, then neither of our plans are going to happen."
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.
The two rivals sat next to one another in swivel chairs in a University of Texas auditorium for the 90-minute debate, one in a dwindling number of opportunities for the former first lady to chart a new course in the presidential race.
She has lost 11 straight primaries and caucuses to Obama — including an overseas competition for support among Americans living aboard — and has fallen behind in the chase for the number of delegates needed to become the presidential nominee.
Obama's strong showing has made him the man to beat in a historic struggle between a black man and a white woman, and even some of Clinton's own supporters conceded she needs victories in both Ohio and Texas early next month to preserve her candidacy. Rhode Island and Vermont also vote that day.
Clinton and Obama articulated well-worn campaign themes in the opening moments of the encounter, she stressing years of experience, and he underscoring a need for a change in the way business is done in Washington.
"I offer a lifetime of experience and proven results," she said, adding that "if we work together, if we take on the special interests," the lives of middle-class Americans would improve.
Obama, too, scorned the power of special interests. "The problem we have is that Washington has become a place where good ideas go to die.... They go to die in Washington because too many politicians are interested in scoring political differences rather than bridging differences get things done."
The Democrats have had at least 18 debates and forums of the campaign, a series that has ranged from highly civilized to hotly confrontational.
The last time the two met, in Los Angeles, they sat side by side and disagreed politely. But in an earlier encounter last month, in Myrtle Beach, S.C., each accused the other of repeatedly and deliberately distorting the truth for political gain in a highly personal, finger-wagging showdown.
In The Associated Press' delegate count Thursday, Obama had 1,358.5 to 1,264 for Clinton. NBC's delegate count has Obama with 1,168 and Clinton with 1,018 and does not include superdelegates. It takes 2,025 delegates to win the Democratic nomination.
In a further sign of his growing strength, Obama won the endorsement during the day of the Change to Win labor federation, which claims 6 million members. The Teamsters union announced its support for Obama on Wednesday.
The debate was sponsored by CNN, Univision and the Texas Democratic Party.