If one of the purposes of political conventions is to give a theatrical expression to our political emotions, then last night’s moment for Senator Kennedy was in the grand tradition. He spoke of “a season of hope” for a stronger future in America, and pledged to be there next January on the floor of the United States Senate. Even for those who disagree on policy with the man from Massachusetts, they were brave words and an affecting moment, all the more so because the senator’s appearance was, given the nature of his cancer, both a kind of farewell and a benediction on the candidacy of Senator Obama. Caroline Kennedy, the late president’s daughter, was, like her uncle, an early endorser of Mr. Obama, declaring at the time that he had the same kind of capacity to inspire that her father had.

Tonight will be the night for Senator Clinton, and it, too, is certain to be an affecting moment. On our Latest Politics blog, Russell Berman reported that at a breakfast yesterday of New York’s 361-member convention delegation, there was “a palpable sense of what-might-have-been.” The “Hillary for President” placards had been replaced by what Mr. Berman called “the more polite ‘Hillary Made History'” signs. He reported that the crowd needed a little warming up. “A morning that would have served as the kick-off to a four-day victory party had instead taken on the feel of a past-tense tribute to New York’s leading lady,” he wrote, quoting Senator Schumer as putting a voice to the mood when he said: “We all do have — most of us, almost all of us in this hall — mixed emotions.”

For her part, Mrs. Clinton was exceptionally gracious. She was greeted with what Mr. Berman called “rapturous” applause, made her thanks, and launched into an endorsement of Mr. Obama. Presumably her words foreshadowed the comments she will make tonight. It is hard to remember a runner up in a presidential primary campaign who had a more intense following than Mrs. Clinton or came as close to winning, and, by our lights, she has been a champion in defeat. It may be, of course, that Mr. Obama will go on to win the election, and if he does, it will be a famous victory. But if he doesn’t, it will no doubt be because he veered left when he should have veered right, and it wouldn’t surprise us to see Mrs. Clinton, four years hence, back in contention.