Washington ? Sen. Barack Obama, D-Ill., might be well advised to stay in the Senate several more years before running for president, as many strategists have suggested. But there are at least 40 reasons to challenge that advice.

That is the number of senators who have tried, and failed, to reach the White House since Sen. John F. Kennedy, D-Mass., accomplished the feat in 1960. Nearly all had more Senate experience than Obama, underscoring the light regard that American voters show for senatorial longevity and expertise in presidential elections.

Questionable strategy

If Obama’s aim is to become a more respected and knowledgeable senator – in the mold of, say, Bob Dole (18 years in the Senate before his 1996 presidential race), Henry “Scoop” Jackson (20 Senate years before his 1972 bid) or Richard Lugar (20 Senate years before his 1996 try) – it may be a laudable goal. But it’s a highly questionable presidential strategy.

“The Senate historically has not been a great place from which to run for president,” said former Sen. Bob Graham, D-Fla., who personally learned the lesson in 2004. “Senator Obama might feel he would be better off to run while he has not been tainted by an excessive period in the Senate.”

In the nation’s history, only Kennedy and Warren Harding have been elected directly from the Senate to the presidency. But the dismal statistics have not dissuaded dozens of senators from trying, including big names (John Glenn, Edward Kennedy), largely forgotten names (Larry Pressler, Carol Moseley Braun) and plenty in between.

Governors preferred

U.S. voters repeatedly have shown a preference for governors, especially during the 52-year stretch from Grover Cleveland’s first election through Franklin D. Roosevelt’s fourth, and again in recent years, when seven of the past eight presidential campaigns have been won by former governors. The 2008 presidential race seems certain to focus special scrutiny on why senators with impressive resumes have fared so poorly in White House bids.

Weighing the choices

Not only did Obama cause a sensation last month by simply saying he would consider a 2008 campaign, but the early front-runners in both parties are senators: Hillary Rodham Clinton, D-N.Y., and John McCain, R-Ariz.

Perhaps no governor will emerge from the pack, as Bill Clinton and George W. Bush did, and 2008 will prove the exception to the rule. But scholars of presidential campaigns have their doubts.

“I’m skeptical that a senator can make it,” said Barry Burden, a political scientist at the University of Wisconsin at Madison who has written on the subject. “Just looking at the historical record, the odds are not very good.”

Burden said voters generally like the executive experience of governors, who are much more able than senators to set their own agendas, make bold decisions, and avoid complicated legislative debates and votes that opponents can exploit.

“The skills that make a person a good legislator are not the skills that make a person a good presidential candidate,” Burden said. “The kind of compromises that make you successful in Congress don’t make you successful in a presidential campaign.”

Vice presidential detour?

Obama, 45 and just two years removed from the Illinois legislature, has a third option that is less viable for McCain and Clinton. He could angle for the vice presidency, a route to the Oval Office for former Sens. Harry Truman, Lyndon Johnson and Richard Nixon – but not for Hubert Humphrey, Walter Mondale, Dan Quayle and Al Gore.

First, however, Obama must sift through the bountiful and conflicting advice of whether to seek the big prize now. Graham, who was Florida’s governor before joining the Senate, said: “My advice would be to lay out a plan of action to have him fully ready to be president in 2013. That schedule would just about coincide with what President Kennedy did” – that is, becoming president after eight years in the Senate.