As we mentioned yesterday, Tim Pawlenty, Rick Santorum, and Michele Bachmann will be joining FRC, the National Organization for Marriage and the Susan B. Anthony List for a “”Values Voter Bus Tour” through Iowa.

In kicking off the event, NOM has announced that Santorum, Bachmann, and Mitt Romney have all signed a five-point “Marriage Pledge” [PDF] that includes a promise to establish a “presidential commission” to “investigate harassment of traditional marriage supporters“: