Joe Biden sometimes talks about the 2020 election like the end of a natural disaster: Having surveyed the wreckage of the Trump years, we'll join together to commit ourselves to setting things right, then get down to the work of the cleanup.

Despite their open disputation, Democrats and Republicans agree on at least one aspect of the unrest that's roiled the summer: The party in charge matters for maintaining public order. But for all their blame-laying, it's become clear.