Poll Tracker

Gallup says it's become a little easier to determine how much of a bounce the presidential nominees get when they announce their running-mate because, in recent years, the choices have become known in advance of the conventions, making it possible to separate its effect from that of the convention "bounce." Gallup says the impact dating back to 1996 has ranged from 3 points to 9 points with the smallest being the George Bush's selection of Dick Cheney and the largest being Bob Dole's choice of Jack Kemp in 1996.