He said that he alternated parties every primary cycle; he said that this provided him with the most campaign literature mailings.
There are times where one "needs" to vote in the opposite party's primary in order to have a say. Decades ago Texas was a "Democrat" state and since some seats would be unopposed in the general election, the only way to have a say was to vote in the primary election.
Some Dem's have gone RINO and have to be defeated in the primary these days.