Last night's debate between Hillary Clinton and Barack Obama was a fairly staid affair with Mrs. Clinton delivering most of the heat as she sought to draw sharp distinctions between herself and Obama:

Sens. Hillary Rodham Clinton and Barack Obama disagreed sharply on how to achieve universal health care, debated about which of them is most ready to serve as commander in chief and argued over who can best change the country as they appealed for support Thursday ahead of showdown primaries in Texas and Ohio.

The Democratic debate began politely but gathered force in the closing portions with pointed exchanges on substantive issues and about the traits required of a president. The forum closed with a flourish, after the candidates were asked to describe how they had dealt with crises in their lives.

Obama answered first and talked about the trajectory of a life that began as the child of a single mother and now finds him as the front-runner for the party's nomination. But it was Clinton who turned the question most to her advantage, alluding to her husband's affair with a White House intern and his subsequent impeachment but then shifting to say that what she went through paled in comparison to the challenges ordinary Americans face every day.

"I think that if your candidacy is going to be about words, then they should be your own words," she said. "That's, I think, a very simple proposition. And, you know, lifting whole passages from someone else's speeches is not change you can believe in, it's change you can Xerox."

But the line fell flat in the hall, and Obama batted away as "silly" the idea that taking the advice of one of his national campaign co-chairmen was plagiarism.