Yes, they can change party, but that applies to all contests, not just the Senate race. In addition, there are four candidates in the Democrat Senate primary, one of who just had a stroke.
I doubt that the crossover vote will amount to much. Crossover is more often seen when one party has only one candidate. However, a more important question is which way would Democrats vote if they voted in the Republican primary?
In PA, there’s no race to speak of for Governor on the Democrat side. There’s supposed to be a 2-way race for Senate between Fetterman (the guy who had the stroke) & Lamb.
But I have yet to see a poll where Lamb is remotely competitive, and Fetterman is the all-but-certain nominee. I thought a year ago that Lamb, the fake “moderate” would win easily over the radical lefties, but apparently the PA Democrats are controlled by the Bernie Bros so the nutjob is going to be the Senate nominee (funny how we never hear that Democrats must move to the center to get elected; only Republicans must do that).
All things considered, Democrats have no real reason to stay in their own yards and can therefore switch over and sabotage the Republican candidates. My guess is that Oz will get the most crossover “mischief” votes from Democrats, who in no way will vote for him a second time in November.