Keyes, 56, announced on his Web site, RenewAmerica, he filed his candidacy Friday with the Federal Election Commission.

He told radio talk show host Janet Parshall he was “unmoved” by what he called the lack of moral courage the other candidates had demonstrated.

"The one thing I've always been called to do is to raise the standard ... of our allegiance to God and his authority that has been the foundation stone of our nation's life,” said Keyes.

Keyes, who held several positions in the U.S. State Department during the Reagan administration, ran for the U.S. Senate from Maryland in 1998 and 1992.

During the 1996 campaign for the Republican presidential nomination, he was briefly detained by police in Atlanta after trying to force his way into a candidates’ debate without an invitation.

Illinois Republicans recruited him in 2004 to run against the Democratic candidate -- and eventual winner -- Barack Obama for a vacant U.S. Senate seat.

Keyes accused Obama during the campaign of taking "the wicked and evil position" on issues like abortion.