This week it was Senator Chris Dodd, D-Conn., who announced his presidential ambitions. Last week, it was Senator Joe Biden, D-Del. The coming weeks could see announcements from Sens. John McCain, R-Ariz., Hillary Clinton, D-N.Y., Barack Obama, D-Ill., Sam Brownback, R-Kan., and Chuck Hagel, R-Neb.
But looking only at the odds, every one is a long shot. Since 1960, 52 senators have tried, but only two have ever managed to ascend straight to the White House -- Warren G. Harding and John F. Kennedy Jr.
"When senators look in the mirror, they tend to see presidents in the making," said Lee Sigelman, an expert on American politics at the George Washington University. "But voters don't tend to see a president in the making when they look at senators."
Sen. John Kerry, D-Mass., was successfully cast as a "flip flopper" in 2004, a job made easier by his two decades in the Senate.
"Senators have long voting records," said Mark Halperin, ABC News' political director and the author of "The Way to Win."
They face other challenges, too.
They "talk like senators rather than leaders," Halperin said. "Senators get trapped in Washington both physically, for votes and hearings, and psychologically. And, senators tend to have more trouble projecting executive experience, which is the kind of job the presidency is."
Some of the senators running in 2008 have even longer careers than Kerry. Dodd has been in the Senate for 26 years, and Biden has one of the longest records there. Now 64-years old, he was first elected at age 29. But Halperin said this could be the year that the curse is put to rest.
"If you are starting from scratch and building a presidential campaign, you wouldn't make your candidate a senator," Halperin said. "But a lot of the senators who are running this time are strong candidates, and a lot of them understand the curse of the senator. … I think it could be the year to overcome."
Sens. Clinton and Obama, Democratic frontrunners, have relatively short Senate careers: Clinton has served six years, Obama just two. McCain, the Republican frontrunner, has served 20 years, but is known as a maverick.
There is another factor this year that could favor senators -- the war in Iraq and national security are major voter concerns heading into 2008, and senators seem well-prepared for the debates ahead. Governors tend to deal primarily with domestic issues, whereas many senators -- including McCain, Clinton and Obama -- tackle foreign policy.
"The fact that national security is going to be a top issue, on the margins at least, will help the senators, because they do have national security experience," Halperin said. "But voters, at other times in American history when security has been the biggest issues, have not turned reflexively to Washington politicians or senators, so it's certainly not a huge advantage."
During the first Iraq War, being governor of Arkansas didn't undermine Bill Clinton. Nor did being governor of California hinder Ronald Reagan as he fought for the presidency during tense Cold War times.
"Lack of expertise on foreign policy has not been a bar to governors in the past," Sigelman said. "The governor may have established his or her record as a competent manager, as a leader, which is obviously the card that George W. Bush played when he was governor. And it's a card that works for governors."