I've long said that the hardest thing about running a political campaign comes, when you're besieged (as you inevitably are) by calls urging you to change your strategy, and you must distinguish the nine instances out of ten when you shouldn't do so from the one in ten time when you should.

If there's one thing that's plain about the strategists at Hillary Clinton's Brooklyn headquarters, led by the millennial wunderkind Robby Mook, is that they failed this test. And there's no better example than their dogged refusal, despite multiple pleas from knowledgeable and concerned Clinton backers, to change their strategy in my home state of Michigan. Edward-Isaac Dovere has some good reporting on this in Politico.

Hillary Clinton chose Mook as her campaign manager, just as she chose to use an insecure private email server when she served as secretary of state. So she's ultimately responsible for the mistakes Mook made in Michigan and elsewhere and for the fact that she violated laws and regulations that predictably made her the subject of a criminal investigation, news about which would quite likely have a negative effect on her campaign.

One of the oldest sayings of political consultants is, "The campaign always reflects the candidate." This one, with its overreliance on centralized command and control and its confidence that it could evade predictable negative consequences of Clinton's actions, most certainly did.