Republicans are calling for a law that would require presidential candidates to provide proof of being born in the United States.

OK, fair enough. But then I'm calling for a law that requires candidates to pass a basic American history exam before being allowed on the ballot.

As the 2012 presidential race begins to take shape, we have potential Republican candidate Sarah Palin insisting that Paul Revere's midnight ride of April 18, 1775, was intended to warn the British that British troops were advancing. (And worse yet, she defended her statement when called on it by a news anchor for Fox, the network that employs her.)

We have fellow potential Republican candidate Michele Bachmann telling an audience in New Hampshire that "You're the state where the shot was heard around the world in Lexington and Concord." Well, at least she got the names of the towns right. Unfortunately, they're in Massachusetts.

And we have declared GOP candidate Herman Cain, who apparently believes that running the Godfather's Pizza chain and hosting a radio show qualifies him to be leader of the free world, recently declaring that the U.S. Constitution guarantees "life, liberty and the pursuit of happiness." Right words, wrong document, Herman. That line is in the Declaration of Independence, not the Constitution.

Before any of these people raise their right hand and put their left hand on a Bible, perhaps they should use both hands to open a history book.