Challenging Ron Kind, Cheri Bustos, and Tim Ryan is not smart. Also why go after Angie Craig, the Minneapolis suburbs are trending D just because she's more vulnerable than Phililps (who is safe) does not mean she is worth targeting. Also I would argue NJ-02 is low hanging fruit, Van Drew's underwhelming margin against a horrible opponent should be concerning to Democrats. Also it is not the right time to Challenge Matt Cartwright, the GOP should work ousting Peterson, the most vulnerable WWC District Democrat
I don't think MN-02 is out of reach just yet. Trump won it IIRC and though the suburbs are trending D hard it's definitely still worth contesting. Jason Lewis was a D-tier candidate and won in 2016.
