— Each election cycle usually produces one ad that voters, pundits and political watchers know will be remembered long after the losing candidate has become a trivia question. In 2008 that ad was the "3 a.m." commercial, which invited viewers to wonder who, in a dangerous world, they'd rather have answering the proverbial "red phone" in the White House. Hillary Clinton may have ended up losing the primary, but she won the ad contest hands down with one of the most effective political ads in recent memory.

This election has produced its own share of memorable ads, among them one that is being touted as potentially effective by some, but racially charged by others. The controversial Romney campaign ad attempts to depict President Obama as the welfare president.

Whether or not the ad is appealing to racism in the electorate may be up for debate, but there's no doubt that is a timeworn strategy in American politics. Plenty of campaign ads over the years have been undeniably racist.

"Hands," 1990

It's not exactly a surprise that a man infamous for whistling and singing the Confederate pride anthem "Dixie" to black Sen. Carol Moseley Braun as an insult would also be responsible for one of the most racially inflammatory ads in American political history. What is somewhat surprising is that the ad in question, which shows the hands of a white man crumpling up a job-rejection letter, was created by a member of a racial minority. During his surprisingly competitive 1990 race for re-election in North Carolina against African-American Democratic candidate Harvey Gantt, the campaign of Sen. Jesse Helms released the ad "Hands." Created by Cuban-American political consultant-turned-CNN-contributor Alex Castellanos, "Hands" engaged in some of the most racially divisive political rhetoric in recent memory, vilifying Gantt as a racial-quota king and, by extension, the great big black bogeyman of working-class white America.

"Debbie Spend It Now," 2012

Somehow former Rep. Pete Hoekstra missed the memo that engaging in gross racial stereotypes can occasionally be perceived as ... well, racist to the group of people being stereotyped. This ad -- which some genius on his campaign staff thought was such a winner that it needed to be aired on Super Bowl Sunday -- engages in some of the most juvenile stereotypes out there about Asians. The ad did end up garnering Hoekstra attention -- but not the kind he was seeking. It was virtually universally denounced -- except by racists.

"Willie Horton," 1988

Though Massachusetts Gov. Michael Dukakis already had an uphill climb in his race for president against then-Vice President George Bush, this notorious ad certainly didn't help matters. While the concept of the ad itself is not necessarily racist (it uses the story of convicted murderer Willie Horton to contrast the two candidates' differing positions on crime policy), the imagery used in the ad is akin to the kind a Klan recruiter might use. Horton doesn't just come across as a criminal, but the ultimate scary black man, and thus the embodiment of every negative stereotype some white Americans held about all black men and all black people.

"The Wave," 2010

Sharron Angle, the colorful Republican candidate who sought to oust Democratic Majority Leader Harry Reid from the Senate, may not have won her race but she did win one distinction. MSNBC's Rachel Maddow declared Angle's campaign the most "overtly racist" of the 2010 election cycle. Angle owes this dubious honor in part to her campaign ad titled "The Wave," which left Latino groups outraged for its depiction of Hispanics crossing the border in "waves" to join "violent gangs." Think this ad couldn't be as offensive as it sounds? Just watch.

Untitled, 1968

Considering he was one of the most notorious segregationists in American politics, this ad by Alabama Gov. George Wallace is fairly tame as far as ads by avowed racists go. But then again, Wallace was running for president, so he knew he had to temper his language to appeal to those Americans who did not use the n-word as a catchall phrase for black Americans. Instead, Wallace talks about harmless sounding ideas like "states' rights." You may find yourself asking, States' rights to do what? Surprise, surprise, he's talking about states' rights to enforce policies like segregation. Well, at least he didn't use the n-word, so we guess he deserves credit for that.

"Give Me Your Cash, B****," 2011

This ad is so racist and over the top that if the world's raunchiest comedian and the Ku Klux Klan had been asked to weigh in before it was posted, they both probably would have said, "Crosses the line." This is most likely why this low-budget ad targeting Democratic congressional candidate Janice Hahn was relegated to the Web. It created quite a splash -- and quite a backlash with its gangbanging rappers surrounded by strippers delivering profanity-laced, misogyny-laden lyrics all in the name of politics. But the backlash turned out to be one of the best things to happen to the Hahn campaign. She won and is currently serving in Congress.

"Welcome Prize," 2010

Considering U.S. Sen. David Vitter managed to survive a prostitution scandal, despite running for office as a social conservative, it shouldn't come as a surprise that he knows how to fight hard -- and fight dirty if necessary for his political survival. His campaign demonstrated this with a series of blistering ads against his 2010 opponent, former Rep. Charlie Melancon. While Melancon probably found most of them offensive, the Hispanic community likely took particular offense at this ad, which, in an effort to vilify illegal immigrants, reinforces appalling stereotypes of all Latinos.

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Keli Goff is The Root's political correspondent.