It has been easy over the years to think that while politicians come and go, Ted Kennedy goes on forever. His dramatic convention appearance last night drove home the stark reality that the days of this 76-year-old senator, suffering from brain cancer, may be limited, and yet it also underscored the legacy he will leave.

Indeed, because of the circumstances, this speech, while briefer than others for which he is celebrated, and with a stiffer delivery, may do more than any other to burnish in people’s minds his image as an orator, a champion of the underdog, and a crusader for health care.

I watched it on television, and I will remember the sea of blue Kennedy signs, and his niece, Maria Shriver, first lady of California, wiping away a tear, and another niece, Caroline Kennedy, biting her lip.

I will remember Senator Kennedy, first elected in 1962, vowing — indeed, pledging — to be back on the Senate floor in January, and renewing his determination, finally, to put across a health care program, a goal he has pursued in the highest-profile fashion since his “sail against the wind” speech to a Democratic gathering in Memphis in 1978. I was there, and one of the commentators was talking about it last night.

The senator’s closing echoed his defiant concession speech at the 1980 convention and the 1961 inaugural of his brother, John F. Kennedy Jr., but it also was forward-looking, anticipating a barrack Obama victory:

“And this November’’ — it came out, of course, Novembah — “the torch will be passed again to a new generation of Americans…The work begins anew. The hope rises again. And the dream lives on.’’

Years from now, when people see on TV, or Web sites, or in museums, clips from this speech, they may miss the essence of the moment if the presentation does not also include excerpts from the broadcasters’ commentary.

“There were a lot of tears here at the Pepsi Center at the Democratic National Convention,’’ said CNN’s Wolf Blitzer.

He added, “You saw a lot of Democrats crying, men and women. There was no doubt about that. This is one of those moments these people who were inside, and millions of people watching around the world...will never forget.

“Ted Kennedy — we didn’t even know if he would make it here to Denver. He made it to Denver. Then we didn’t know if he’d be strong enough to deliver a speech. But what we heard, and a lot of us have heard Ted Kennedy over the years, this was a powerful vintage Ted Kennedy making his point.’’

CNN’s John King, who hails from Boston, couldn’t resist saying it was nice to hear someone with “the right accent.’’ Then he filled in some of the background to the senator’s appearance, that he got out of his car at a loading dock, was put in a golf cart, brought backstage, waved to people, but said nothing. There was, he said, uncertainty as to whether he actually could go on, or perhaps would go out there but have to sit on a stool that had been placed on stage.

But he did stride out, and none of this stool stuff, and he did speak, and why not? As King said, “The guy wanted to be here…Whatever you think of his politics, he is a lion, and I think he proved it tonight.’’

On ABC, Charles Gibson called it “as emotional a moment as you can see at a convention,’’ and Diane Sawyer said 20,000 people “held their breath as one.’’

On Good Morning America this morning, Rhode Island's Rep. Patrick Kennedy couldn’t stop beaming about his father.

The congressman said someone told him the speech had been his dad’s “Michael Phelps moment.’’

Sounds about right to me.

M. Charles Bakst is The Providence Journal’s political columnist.

mbakst@projo.com / (401) 277-7638