The Senate's "Liberal Lion" has waited a lifetime for the political battle now being waged in Washington.
As he stays home in Massachusetts getting treatment for a brain tumor, surrounded by family, and sailing whenever he can, colleagues said Kennedy is monitoring the health care debate via C-Span.
His absence from Washington now is painful for him, according to friends. Even some of his adversaries can't help but wonder how things would be different if Kennedy was in Washington, leading the debate.
"One of the biggest problems is unifying the Democrats. And to be honest with you, he's the only person I know in the Democratic Party who could bring together its five largest groups," Sen. Orrin Hatch, R-Utah, a long time colleague, who has been both an ally and rival to the ailing Kennedy's health care efforts.
Kennedy watches the hearings on TV and reads the news clippings his wife, Vicky, brings every morning, but his most important role now is an inspirational one. Friends, hoping to tap the emotion of his speech last year at the Democratic convention, talk about winning one more for Teddy.
"This is the cause of my life," Kennedy said in a rousing speech at the Democratic convention in August. "That every American -- north, south, east, west, young, old -- will have decent quality health care as a fundamental right and not a privilege."
The passage of health care reform has been stalled, with even some Democrats wavering in their support.
Democrats are keenly aware that Kennedy's vote may ultimately make the difference between success or failure. That's why Senate leaders hope that when it comes time for a final vote, he will be here to raise his hand one more time, no matter what it takes to get him to Washington.
"I would think if they could get a bill put together, he'd be one of those who'd want to be there," Hatch told ABC News.
Kennedy has arrived for other votes several times since his diagnosis, but it's been three months since the last return.
On one of Kennedy's rare returns to Washington, even the president takes notice, saying during one recent appearance in March, "It is thrilling to see you here, Teddy."
Sen. Kent Conrad, D-N.D., conceded Democrats would have to take more time and seek Republican support.
"Look, there are not the votes for Democrats to do this just on our side of the aisle," Conrad said. "It is not possible and perhaps not desirable either."
Sen. Chris Dodd, D-Conn., who is guiding the bill through the Senate in Kennedy's absence, keeps in frequent touch. But Kennedy's influence is said to be limited by his increasing difficulty communicating.
In Kennedy's absence, his colleagues invoke his name, hoping also to borrow his legislative prowess.
"Sen. Kennedy, wrestling with his own health care crisis at this hour and has been unable to be with us," Dodd said in a speech Friday on the Senate floor.
"Senator Kennedy's presence was palpable," Senate Democratic leader Harry Reid, D-Nev., said the same day, discussing his colleague's effect on the health care reform debate.
Kennedy's Absence Felt on Both Sides of the Aisle
Kennedy and Hatch have long had an unusual partnership that has spanned decades, one that has allowed them to combine on numerous pieces of legislation and left the two men with what, by all accounts, is a genuine affection for one another.
"We've passed a lot of bills together, and we've done an awful lot together. I have a great deal of feeling for him," Hatch said.
When the two work together, Hatch said, "He gets all the credit. I get all the blame. The conservatives can't understand why I'd have anything to do with him. But actually he's a very good legislator. He's a very, very fine friend. I pray for him every day that he might get well."
Obama now wants a health care reform bill he can sign by the end of the year. That job is made more difficult by the absence of the issue's top advocate on Capitol Hill.