Sen. John Kerry (D-Mass.) ended speculation about his political future Wednesday afternoon, saying that he would seek re-election to the Senate in 2008 rather than pursue the presidency again.

After a lengthy and impassioned speech on the Senate floor about the Iraq War, Kerry ended by saying he would channel his energy into shaping successful Iraq policy from the Senate.

Kerry said he will do “whatever I can to ensure that the next president can take the oath of office with the reasonable prospect of success” in Iraq.

Kerry, who famously said during the 2004 campaign that he “actually did vote for the $87 billion before before I voted against it” in regards to a supplemental spending bill funding the war, made clear that he regretted his 2002 vote to grant President Bush the authority to invade Iraq.

“As someone who made the mistake [of voting for the war] I feel the weight of personal responsibility to act,” he said.

By announcing his intention to seek a fifth Senate term, Kerry dashed the hopes of several of his Bay State colleagues in the House who were hoping to succeed him in the Senate.

For his encore, Kerry is asking his supporters — he amassed a 3 million person strong e-mail list during his presidential run — to support his new venture, www.setadeadline.com.

The new Web site is meant to pressure Bush into establishing a deadline for withdrawing U.S. troops from Iraq.

— Nicole Duran