This article is part of the Opinion Today newsletter. You can sign up here to receive the newsletter each weekday.

Donald Trump has survived so many political scandals that he can sometimes seem invincible. But he isn’t. He is an unpopular president whose party just suffered a big defeat in a midterm election, which shows that many of the normal rules of politics do indeed apply to Trump.

And now he is becoming even weaker.

Yesterday was a very bad day for the president. His former lawyer, Michael Cohen, was sentenced to three years in prison for a set of crimes — “dirty deeds,” in Cohen’s words — some of which he committed at Trump’s direction. Separately, prosecutors announced that they secured the cooperation of the company that owns the National Enquirer, which apparently helped pay hush money on Trump’s behalf.

I know what you may be thinking: Trump’s allies will stick by him, regardless of what happens. I disagree. Already, there are early signs of waffling from Trump’s usual allies.