U.S. Vice President Joe Biden
US Vice President Joe Biden prepares to introduce President Barack Obama at Lackawanna College in Biden’s hometown of Scranton, Pa., on Aug. 23, 2013. Reuters

More than ever, political candidates have to watch their every word. And they have opposition trackers and anyone holding a video camera at campaign events to thank. One slip or gaffe recorded on video can damage a campaign. U.S. Senate candidate George Allen of Virginia, congressional candidate Allen West of Florida and 2012 presidential candidate Mitt Romney learned that the hard way, as their verbal faux pas helped contribute to their losses.

Below is a look at some of the most memorable -- and damning -- political blunders captured on video.

George Allen, the former governor of Virginia, didn’t help himself in his tight race for the U.S. Senate with Democratic candidate Jim Webb after referring to an Indian-American opposition tracker with Webb’s campaign as “Macaca.”

Tea-party darling and ex-U.S. Rep. Allen West’s re-election campaign in Florida was predicted to be a close race, but the nail-in-the-coffin moment may have been when the controversial congressman put an exact figure on how many Democrats in Congress he believed were communists. The comment was given in answer to a question posed by someone in the audience during a town-hall meeting (West lost to his opponent, Patrick Murphy, by fewer than 2,500 votes).

Mitt Romney’s hopes of defeating President Barack Obama in the 2012 election were dashed when he made “47 percent” the defining moment of the campaign. The remark, referring to the proportion of Americans Romney said rely on government programs and would never vote for him, was captured during a fundraiser at private-equity manager Marc Leder’s home in Boca Raton, Fla.

The damage isn’t just limited to Republicans, however (although the GOP is trying to get even, as you can read in this International Business Times Magazine piece here.) While not seen as a top-tier contender for the Democratic presidential nomination in 2008, then-U.S. Sen. Joe Biden of Delaware didn’t help his chances when he made a remark about Indians working at Dunkin’ Donuts.