If resumes won presidential nominations, Sen. Bob Graham might be the Democratic front-runner.

The 66-year-old Florida Democrat served two successful terms as governor and is in his third Senate term. As chairman of the Senate Intelligence Committee, he gained intimate knowledge of foreign policy after Sept. 11, 2001.

A political moderate, he has been a big vote-getter in the state that decided the last presidential election and could be crucial in the next one. He has had a flawless personal life.

But if Graham runs after recuperating from recent heart surgery, he will face an uphill fight. While he probably can raise substantial funds, he barely is known to activists in Iowa and New Hampshire. If he tries to bypass them, he will challenge their historical role.

Besides, he will have to surmount the jokes over his habit of recording every detail of his activities in color-coordinated notebooks.

Then, there is Gary Hart, the one-time Colorado senator.

Also 66, he apparently feels his long focus on defense and foreign policy and early warnings on the need for enhanced homeland security outweigh any damage from the highly publicized extramarital relationship that derailed his 1988 presidential bid.

The mastermind of George McGovern’s 1972 campaign, he provided one of the more memorable comparisons of the current race when The Hartford Courant’s David Lightman asked why he had chosen now for a comeback.

“Why did Winston Churchill come back after 10 years out of office?” he responded with his own question. “Times change.”

He repeatedly has acknowledged frustration that his 1987 dalliance with Donna Rice cost him a chance to lead the nation and moderate the Democratic Party, as Bill Clinton later did.

“It was frustrating because I think I did have something to offer,” he said on the Fox News Channel. “And to be denied that opportunity because of that single incident.”

Of course, many Democrats saw the Rice episode as part of a pattern, much like Clinton’s later relationship with Monica Lewinsky. Ironically, Hart may suffer because Democrats don’t want another embarrassment.

Graham’s and Hart’s prospective candidacies aren’t the only potential uncertainties in the wide-open Democratic race.

Rep. Dennis Kucinich of Ohio hints he will throw his populist hat into the ring. Former Illinois Sen. Carol Moseley-Braun says she may give the race a second African-American. Gen. Wesley Clark, the ex-NATO commander, shows signs of running. And Sens. Joe Biden of Delaware and Chris Dodd of Connecticut are mulling candidacies.

Though it may take a greater surprise than most presidential races produce for them to be serious contenders, the uncertainties that can arise were underscored this week when Sen. John Kerry of Massachusetts underwent prostate cancer surgery.

Word of his illness came at a time that a consensus had started to form that Kerry was emerging as the Democratic front-runner.

The one-time Vietnam War hero who became a leader of the anti-war movement has benefited from shrewd hiring, good poll results and a favorable political calendar though he has drawn some fire for trying to balance criticism of President Bush’s Iraq policy with likely support for an attack on Saddam Hussein.

The early leader in the national polls is Sen. Joe Lieberman of Connecticut, the unsuccessful 2000 vice presidential nominee. But he doesn’t lead in any of the states likely to hold the first tests, and he has been slow to organize a campaign and develop a strategy.

The others also face challenges.

Rep. Dick Gephardt of Missouri, a 1988 also-ran, will formally announce next week. He must show he isn’t yesterday’s candidate.

Sen. John Edwards of North Carolina, a relative neophyte, must show he isn’t tomorrow’s.

Former Gov. Howard Dean of Vermont must show he is more than a liberal curiosity and can fund a national campaign.

The Rev. Al Sharpton must show why, having never held public office, he should be taken seriously.

And Kerry must show how, as a Massachusetts liberal, he isn’t another Michael Dukakis.

So there may be room yet for Bob Graham and Gary Hart!

Carl P. Leubsdorf is Washington bureau chief of the Dallas Morning News.