WASHINGTON – Like many presidential wannabes before him, John Kerry must now decide what to do with the rest of his political life.

As he relaxed at his Boston home Friday, his friends, colleagues and presidential historians said they don’t see Kerry fading away into political obscurity, as fellow Massachusetts Democrat Gov. Michael Dukakis did after his 1988 run for the presidency.

Instead, they said he will probably take the road less traveled by recent senators who tried and failed to take the White House, and become a stronger voice in Congress on issues he cares about.

“He has a lot to say,” Kerry’s former chief of staff David Leiter said Friday. “Dukakis faded into the sun. I don’t see that in Kerry.”

Dukakis agreed. In a Senate that just lost Democratic leader Tom Daschle in a narrow South Dakota race, Kerry “could become a very strong voice for a strong opposition,” said Dukakis.

“It was a very impressive performance and he came damn close,” said Dukakis. “I think it’s important for him to build on what he’s done and at the very least to be a major leader in the party and in the Senate.”

Most agree, however, that he’s not likely to get another shot at the presidency.

“Nowadays, these election cycles are so excruciating and they last so long, there’s a feeling that there’s a need for a fresh face,” said presidential historian Doris Kearns Goodwin.

History is filled both with senators who came back and those who cleared out.

Hubert Humphrey, who was vice president from 1965 to 1968, flirted with the presidency several times, but always returned to the Senate, where he served until he died in 1978.

His run for president in 1960, when he lost the nomination to John F. Kennedy, was “the same kind of tough election campaign that I think Kerry went through,” said Steve Sandell, director of the Humphrey Forum at the University of Minnesota. “It was very tough for him to get over those [primary] defeats, but he was a very resilient guy. It’s a good example for Kerry.”

Kerry’s Massachusetts colleague, Sen. Edward M. Kennedy, ran for the Democratic nomination in 1980 and lost, and came roaring back to the Senate to become one of its most powerful voices.

Perhaps the most vivid comeback was that of Richard Nixon, who, after losing the presidency to Kennedy in 1960 and a gubernatorial race in 1962, delivered the now-famous line: “You won’t have Richard Nixon to kick around anymore.”

Six years later he became president.

But in recent history, presidential losers have been more inclined to leave politics.

Democrat Al Gore, who lost the 2000 election by a handful of votes, retreated almost immediately into self-imposed exile after his defeat. Republican Bob Dole, who resigned from his Senate seat to run for president in 1996, became a television pitchman for Viagra, and is now a Senate husband. His wife Elizabeth is a senator for North Carolina.

Dukakis served out his remaining two years as governor, but left the public spotlight for good in 1990 to become a college professor.

The shift over time may be attributed in part to how long presidential campaigns have become. Almost immediately after Gore lost, Democrats, including at least a half dozen in the Senate and House, began jockeying for position. The 2004 campaign began in earnest a full two years before Election Day.

“In the old days, [senators] felt the Senate was the pinnacle of political ambition,” said Kearns Goodwin. “They felt they could make a difference there, there was a great deal of respect and honor to be a senator.”

Now, she said, “they look at each other and think, if he can run for president, why can’t I?”

Kerry has said little publicly about his intentions, except to vow on Wednesday that he will “fight on” in the Senate, where he has served for 20 years. His term expires in 2008.