The American Humanist Association (AHA) recently kicked off a national campaign to remove the words "under God" from the Pledge of Allegiance.

The campaign consists of YouTube ads and bus stop posters in select cities, encouraging people not to say the pledge, The Washington Times reports.

The short phrase "under God" has been the source of contentious debate for years, but atheists have so far been unsuccessful in legally changing the national oath. AHA Executive Director Roy Speckhardt hopes that by educating Americans about the pledge's origin, they may have more support for their cause.

"We want everyone to know that the current wording of the pledge discriminates against atheists and others who are good without a god, and we want them to stand up for fairness by sitting down until the pledge is restored to its original, unifying form," Speckhardt said in a statement.

One of the ads is written on a chalkboard, and notebooks, books, and a clock surround the bulletin:

"Did you know: 'Under God' wasn't originally in the Pledge of Allegiance?

"It was added in 1954 to separate America from 'godless' communism.

"'Under God' discriminates against atheists, agnostics, and humanists."

The ad includes the AHA logo, and a message that is directed toward students: "America is one nation indivisible. Take a stand by sitting down. Dontsaythepledge.com."

"Through the daily pledge exercise, our public schools are defining patriotism by promoting god-belief while stigmatising atheist and humanist children," AHA Appignani Humanist Legal Center Legal Director David Niose said. "This violates the principles of equal rights and nondiscrimination, which is why we are currently challenging 'under God' in the pledge with a lawsuit in New Jersey."

The AHA filed a lawsuit in March against the Matawan-Aberdeen Regional School District in New Jersey on behalf of an atheist family. The family objected to their child saying the Pledge of Allegiance in class, although both the district and the parents acknowledged that the child is not being forced to participate in the recitation.