For all the rhetoric in campaign kickoffs about running on issues, sometimes a well-executed attack is what finishes a race. Fact-based claims that strike a chord with voters can strike a fatal blow in a close campaign.

Political attacks are almost as old as our Democracy but are nearly inescapable with modern mass media. In 1800, Federalists wrote that “murder, rape, adultery, and incest” would follow Thomas Jefferson into power; his supporters fired back that John Adams was “one continued tempest of malignant passions.” Attacks jumped onto television in 1964, with LBJ’s “Daisy” ad—which ran just once but helped sink Barry Goldwater. Even in 2008, the year of “hope,” plenty of mud was slung. “Campaigns have been getting really dirty for years,” says political science professor Kerwin Swint, and the fast approaching midterm elections could follow right along. “2010 is going to be right up there with the dirtiest of the last 20 years,” Swint says.

We’ve rounded up a few of this century’s toughest finishing moves so you can see what works—and what doesn’t. Be prepared: you may have to play rough to win.