Take one more "potential" presidential candidate off the list. Massachusetts Senator John Kerry won the 2004 Iowa Caucuses, a victory that helped him secure the Democrat Party’s last presidential nomination.

"We came close, certainly close enough to be tempted to try again," Kerry says. "There are powerful reasons to want to continue that fight now, but I’ve concluded this isn’t the time for me to mount a presidential campaign."

Kerry made several trips to Iowa after his 2004 loss to President Bush, holding open the possibility he would run again. Instead, Kerry has decided to remain in the Senate and run for reelection in 2008. He made the announcement this (Wednesday) afternoon during a speech on the floor of the U.S. Senate.

"I intend to work here to change a policy in Iraq that threatens all that I’ve cared about and fought for since I came home from Vietnam," Kerry said, as his voice started breaking. "The fact is that what happens here in the next two years may irrevocably shape or terribly distort the administration of whichever candidate is next elected president." There are several other senators who are running for president.

For example, New York Senator Hillary Clinton, Illinois Senator Barak Obama and Kansas Senator Sam Brownback all announced they were running last week. Clinton is due to campaign in Iowa this weekend. Obama’s set to visit the state the first weekend in February.

Here’s a list of other U.S. Senators who are mulling campaigns for the White House or are running already: Delaware’s Joe Biden, Connecticut’s Chris Dodd, Nebraska’s Chuck Hagel and Arizona’s John McCain who is listed in many early public opinion polls as the frontrunner for the Republican Party’s next presidential nomination.