The midterms in motion

Early advantages are emerging, but so are the constraints that could blunt them.

Midterm season is fully upon us, meaning that some things are becoming more clear while in other domains there is a real uptick in chaos. A late-night Trump endorsement may reshuffle the California governor’s race amid his new mail-in voting instructions, and fresh polling on “double haters” confirms the obvious — independents are not happy.

The polls a…