Joe Biden’s reference to Barack Obama as “clean” won’t do the Democrats much harm. But Obama’s description of religious, rural folk as “bitter” just might. You just never know which political gaffes will do the most harm, Jonathan Alter writes in Newsweek. “Modern campaigns are about flinging 10 things against the wall every day and hoping something sticks,” he says.
The most harmful goofs feed into public perception about a candidate—like Dan Quayle misspelling potato. "Sticky" ideas don’t even have to be true to be effective. Al Gore never claimed to have invented the internet, and Obama isn’t Muslim. But both falsehoods worked against the candidates, Alterman notes. “Flaps fade,” Alterman writes. But some "images and gaffes act like a piece of gum on the bottom of your shoe and may shape voting behavior."