Yes, a majority of Americans still favor the death penalty. But that majority has plummeted over the last two decades, as the Pew Research Center found last year.

In 1996, 78 percent of Americans were in favor of capital punishment while just 18 percent opposed it. In 2013, support had fallen to 55 percent while opposition had risen to 37 percent. (If you don’t feel like doing math: The gap between supporters and opponents shrunk by 42 percentage points, a pretty huge swing.)

So what happened? Well, revelations about mistakes and wrongful convictions “exposed the fallibility of the system,” according to Richard C. Dieter, executive director of the Death Penalty Information Center. A recent study found that at least 4.1 percent of people sentenced to death would be exonerated (“a conservative estimate,” as the study’s authors noted).

Scott Clement has more at The Fix about how lethal injection remains the favored form of capital punishment in this country — something that could be threatened by two botched executions in the first four months of this year.