I bet the money people were not ready to fund another attempt given his propensity toward foot in mouth disease:

Democratic Sen. John Kerry of Massachusetts, who lost the 2004 election to President George W. Bush, will not make another run for the White House in 2008, party sources said on Wednesday.[…]He was forced to apologize and cancel all his campaign appearances in the week before the 2006 congressional election after he made what he called a “botched joke” about troops in Iraq that prompted a storm of Republican criticism.Several Democrats distanced themselves from Kerry ahead of November’s election.

Read the rest here.The field is crowded and he had his chance and couldn’t close the deal. I’m just surprised that he had the wisdom to see the handwriting on the wall.Update: Here’s a video of Kerry making the announcement.(via)