The trial of Bill Cosby provides what social scientists might call a natural experiment. In the spring of 2017, a jury could not agree on whether Mr. Cosby had drugged and sexually assaulted Andrea Constand, setting the stage for a retrial.

But between that trial and this one came the revelations over Harvey Weinstein and a cascade of other powerful men that invigorated the #MeToo movement. The big question: would it make any difference?

It well may have. The jury deliberated not even two days — compared with six days the first time around — before finding Mr. Cosby guilty on all counts.

There were other key differences: Jurors saw a new defense witness, who testified that Ms. Constand had said it would be easy to use fabricated abuse claims to extort a celebrity.