That is the trouble.
Here in Pennsylvania and around the country, RINO’s stop at nothing to maintain power in the primaries. They will run third candidates to split opposition votes when an outsider challenges an insider.
The parties are closed here with members only in primaries and indies can’t vote in primaries of either one.
Independent candidates have a higher threshhold of signatures to get on the ballot.
Arlen had no option but to go Democrat under that system.
The best part of the Arlen thing is everybody knows it. Even the MSM can’t provide cover for that move.