Hence the difference between McCain in 2008 and Romney in 2012.

Via The Hill:

Mitt Romney won’t ask his supporters to stop heckling President Obama and his surrogates at campaign events.

During a radio interview on Tuesday, the presumptive GOP nominee declined an opportunity to ask his supporters to stop, saying his campaign didn’t “believe in unilateral disarmament.”

Supporters of the president have, in return, begun heckling Romney during his five-day, six-state bus tour this week, disrupting campaign events in Ohio and Pennsylvania. But Obama adviser David Axelrod condemned the tactic on Twitter Monday, urging the president’s supporters to back down.