RICHMOND, Va. - Former GOP Gov. Jim Gilmore announced Monday that he will seek the U.S. Senate seat held by retiring Republican John Warner. Gilmore's announcement sets up a campaign with another former governor, Democrat Mark R. Warner — a clash between two men with vastly different views about government and little affection for the other. Mark Warner announced his intent to run for the seat in September and raised more than $1.1 million in just 17 days.