If you want to vote in the Virginia Republican primary, you'll have to sign an oath swearing to vote for the Republican presidential candidate in the general election, whoever he might be.
No, I'm not kidding.
Since the Virginia primaries are open -- you don't have to register as belonging to a party in order to vote in its primary -- the GOP is worried about Democratic spoilers messing with the results. This unenforceable and bizarre oath is supposed to prevent that somehow.