U.S. Democratic presidential candidate Howard Dean may have achieved political immortality, writing himself into the annals of U.S. presidential campaign lore with his primal scream on Monday night. Dean defiantly rolls up his sleeves, in this file photo, as he comes on stage to concede defeat in the 2004 Iowa Caucuses to rival candidate U.S. Senator John Kerry in West Des Moines, Iowa January 19, 2004. Dean vowed "We will fight on." US ELECTION REUTERS/Jim Bourg JRB/TRA