http://electionlawblog.org/?p=62528
Here is the gist, as the rest was overturned when Dims realized they were shooting themselves in the foot:
In addition, the state Democratic Party sued Gov. Haley Barbour and others in the mid-2000s regarding just that matterprompting United States District Judge W. Allen Pepper to write in a June 8, 2007, opinion that it is the responsibility and right of the political party holding a primary election to ensure that the elections are fair and legal. In the case of a Republican primary and runoff, only Republicans vote, and in the case of a Democrat primary and runoff, only Democrats voteand it is the role of the political parties to ensure that process is handled correctly.
The Supreme Court determined in a 2005 case that the First Amendment protects the right of political parties to associate with fellow members and disassociate with non-members, Judge Pepper wrote in his opinion. So technically its the partys responsibilityi.e., in this case, state GOP chairman Joe Nosefs responsibilityto protect GOP voters First Amendment rights by working to keep Democrats from voting in the GOP primary runoff.
Thank you VERY much. Greatly appreciated.