Politico has this article by Rob Richie and Elise Helgesen, exploring the point that Republican national bylaws, if enforced, may lead to credentials challenges at the Republican national convention that convenes August 27, 2012. The bylaws say that states choosing delegates before April 1 must not use the “unit rule” (a rule that forces all delegates from one particular state to vote for the candidate preferred by a plurality of the delegation). Also, the bylaws deprive states that choose delegates as early as January half their delegates. And, the bylaws even require closed primaries for choosing delegates.
It is possible that the national convention will enforce some of these rules but not all of them.