Former Congressman Charles Bass of New Hampshire has this op-ed in the Washington Post, predicting that New Hampshire election authorities will keep Bernie Sanders off the 2016 Democratic presidential primary ballot.
Bass probably doesn’t know that in 1986, the U.S. Supreme Court said in Tashjian v Republican Party of Connecticut that political parties have an right to nominate non-members if they wish. Clearly, if parties are free to nominate non-members, they certainly have a right to see to it that non-members are permitted to run in their primaries. It is true that the comments about political parties nominating non-members was only dicta. However, it is persuasive dicta, and it caused a state court in Colorado and a federal court in New Mexico to invalidate state laws barring candidates from primary ballots if they hadn’t been members of those parties long enough.
It is true the South Dakota Libertarian Party lost a lawsuit on this issue in 2014, but that is because the party’s own bylaws said the party only wishes to nominate members, so the party’s own bylaws sabotaged the party’s lawsuit.
The Republican Party nominated a Democrat for Vice-President in 1864, and there is reason to believe that when the Republican Party nominated Dwight Eisenhower for President in 1952, he was a registered independent in New York.