However, the "jungle primary" also has an effect. Since the top two vote getters irrespective of party go to the general election, you can't just squeak by a primary and then cruise to victory in a safe district (the Tea Party tactic). The minority party gets to weigh in at the general, so if two Republicans or two Democrats go to the general, the more moderate one is going to likely pull more votes from the minority party.
This pulls people closer to center which tends to favor Democrats.
Can you give a specific example of a district where this effect was observed in a real election? i.e. where the Republicans would have won a seat because of a radical (of either party) winning a primary, but ended up losing the seat because of the “jungle primary”.
It's plausible under the assumptions that Democrats tend to field a moderate candidate in their primary and Republicans don't. That seems pretty reasonable to say right now, but might be less true in a few years as die-hard progressives mount our own "Tea Party"-style insurgency within the Democratic Party.
However, the "jungle primary" also has an effect. Since the top two vote getters irrespective of party go to the general election, you can't just squeak by a primary and then cruise to victory in a safe district (the Tea Party tactic). The minority party gets to weigh in at the general, so if two Republicans or two Democrats go to the general, the more moderate one is going to likely pull more votes from the minority party.
This pulls people closer to center which tends to favor Democrats.