After exploring the possibility of a run in several previous cycles, in January 2007, Biden declared his candidacy in the 2008 elections. During his campaign, Biden focused on the Iraq War, his record as chairman of major Senate committees, and his foreign-policy experience. In mid-2007, Biden stressed his foreign policy expertise compared to Obama's. Biden was noted for his one-liners during the campaign; in one debate he said of Republican candidate Rudy Giuliani: "There's only three things he mentions in a sentence: a noun, and a verb and 9/11."