For the primary ballot - however, that law applies both to the primary and general elections. Should Paul somehow get the GOP nomination for President and win the primary, he would either have to leave his name off the ballot for President, tossing away 8 electoral votes off the bat, or withdraw from the Senate race, awarding the Democrats an instant gain in the Senate as a replacement could not be named if he drops out.
If cats and dogs start living together and Rand Paul wins the GOP presidential nomination, he will drop out of the Senate race and permit the state GOP to name his replacement on the ballot. Rand is a Paultard, but he’s not actually retarded.
The reason for Rand’s hissy fit is because he wants to run for president while filing for reelection for when he loses (like his daddy used to do), and if KY had a presidential primary he would not be able to appear on that ballot while simultaneously appearing on the Senate primary ballot. This way, he can stay in the presidential race past late January (which is the filing deadline in KY), so that he can get a bunch of third-place finishes like his daddy used to do. But maybe Rand can “win” the USVI caucuses (with like 50 voters) like Ron Paul did in 2008.