“The good news that Democrats can’t vote in the Republican primary.”
They can and they will.
There’s really no such thing as a “closed” primary. All Democrats need to do is to switch parties (temporarily) and bingo! They get to vote as “Republicans” in the primary and try to sabotage the candidates who stand the best chance of winning in November so they’ll vote for Oz — tomorrow. But not in November.
The only difference between a supposedly closed primary state like PA and an open primary like so many other states have, is that you have to put a *little* more effort into switching.
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?