The Volokh Conspiracy - What Did They Do?

This puzzle comes to us courtesy of VC friend James Taranto:

Richard Nixon did it three times.

Jimmy Carter, Ronald Reagan and Bill Clinton all did it twice.

Barry Goldwater, Walter Mondale, Michael Dukakis and Bob Dole all did it, but Hubert Humphrey, George McGovern and John Kerry did not.

Abraham Lincoln and both George Bushes failed to do it twice, and William Jennings Bryan failed three times.

What is it?

If you've figured it out, please post some other examples of people who have and have not done it before giving away the actual solution.

	[Puzzleblogger Kevan Choset, October 11, 2005 at 2:10pm] Trackbacks What Did They Do? This puzzle comes to us courtesy of VC friend James Taranto: Richard Nixon did it three times. Jimmy Carter, Ronald Reagan and Bill Clinton all did it twice. Barry Goldwater, Walter Mondale, Michael Dukakis and Bob Dole all did it, but Hubert Humphrey, George McGovern and John Kerry did not. Abraham Lincoln and both George Bushes failed to do it twice, and William Jennings Bryan failed three times. What is it? If you've figured it out, please post some other examples of people who have and have not done it before giving away the actual solution.