Scott Walker's bizarre reason for dropping out of the race was characteristically Nixonian. Citing Ronald Reagan, Walker said he was dropping out in order to lead others to do the same thing because the whole campaign has just gotten so negative.

"I encourage other Republican presidential candidates to consider doing the same so the voters can focus on a limited number of candidates who can offer a positive, conservative alternative to the current frontrunner," said Walker.

Is that what Republicans mean when they talk about leading from behind?