As the presidential race heats up, vice-presidential expert Joel Goldstein discusses how the role of the nation's No. 2 has changed over the decades.
The vice-presidential debate Thursday might not change much in the polls, but it should provide more zingers than the first presidential debate did – and be a warm-up for Obama-Romney Round 2.
In the left corner, comedian Jon Stewart. In the right corner, Fox News shout-meister Bill O'Reilly. What might they achieve, besides self-promotion, when they face off Saturday night for a political debate?