Democrats worried about an expensive primary war for Dianne Feinstein's seat

[IceSpear]

When are Democrats ever not worried about something? Talk about overreaction. The Republican Party was subject to a hostile takeover last year and they constantly have competitive, divisive, expensive primaries (occasionally even in swing states and blue states!) Clearly that's really taking a toll on them politically.

[IceSpear]

Remember when a 2014 Republican bitter primary  caused Democrats to pick up a Senate seat in Mississippi? This could happen again, but in California and to Democrats!1

To be fair, Philanderin' Chris would have probably lost to Childers had he been the nominee. So that's not a very good example, even though I agree with your larger point.

In 2014? When Republicans won nearly every competitive race? That seems highly unlikely.