"Who am I? Why am I here?" That's probably not how a vice presidential candidate should open a nationally televised debate.
But retired Navy Adm. James Stockdale, running mate of 1992 third-party candidate Ross Perot, did just that in a shaky attempt at humor.
Debates between No. 2s seldom shape election outcomes. Yet they've provided some of politics' most colorful moments.
Clearly, the stakes are higher than usual in Thursday's debate in Danville, Ky., between Vice President Joe Biden and Republican Rep. Paul Ryan. The race is extremely tight, both candidates are Washington heavyweights and President Barack Obama's fumbles in his first debate with Mitt Romney have raised expectations on both sides.
Biden, although a seasoned debater, has a history of gaffes. And Ryan, chairman of the House Budget Committee, can come across as wonkish and numbers-focused.
Republican vice presidential nominee Sen. Bob Dole drew wide criticism for his talk of "Democrat wars" in his 1976 debate with Walter Mondale -- the first-ever televised running-mates' debate.
Democrat Geraldine Ferraro scored points by lashing out at Vice President George H.W. Bush for a "patronizing attitude" on foreign policy in 1984. But the encounter is remembered by many for Bush's boast a day later that he'd tried to "kick a little ass."
Sen. Lloyd Bentsen famously put down Sen. Dan Quayle with his "you're no Jack Kennedy" zinger in 1988. Quayle may have lost the debate but he and George H. W. Bush won the election.
Alaska Gov. Sarah Palin, the GOP's No. 2 in 2008, greeted Biden cheerfully: "Hey, can I call you Joe?" Sure, he said, but later she needled him by repeatedly and sarcastically calling him by his first name.
President Barack Obama was campaigning Thursday in Miami. Romney was in Asheville, N.C.