Missouri Democrats will be back, but it will be a long haul.
That is for sure.
Democrats should not rule out Missouri, however.
That's right. Remember that a minimum wage increase ballot initiative passed overwhelmingly in MO on the same day McCaskill lost. That should provide a hint as to what electoral strategy would work better for Democrats here.
Ballot measures like a minimum wage increase can pass because it's a singular idea. Democratic candidates have to stand on a platform that includes a wide range of ideas. Being a Democrat comes with a label that opens them up to attack on immigration, abortion, guns, etc. which makes running a good campaign there very difficult. Look at Medicare for all: lots of Democrats didn't even endorse the idea when they ran but because of the (D) Republicans ran ads against them saying they did endorse M4A and many voters were inclined to believe it.
My point was that McCaskill would probably have performed better had she tied herself more closely to that minimum wage ballot initiative (she might have won, or she might have made the final result a nail-biter for her opponent). Instead, she actually alienated Democratic base voters during her campaign, which depressed turnout in Democratic base areas and greatly contributed to her loss (remember, polls suggested that she would either win narrowly or lose narrowly, both of which suggested that the actual result was an underperformance).