It was a revealing riff, one that Trump has used many times before, and makes sense in his confrontational worldview: as long as an enemy somewhere is engaged in bad behavior, there’s little point fretting about the goodness of one’s own.

In the case of the debate, Trump brought up ISIS when talking about his own personal conduct. Usually, though, he’s brought up the same descriptions of executions while rousing audiences with talk of war crimes.

“The enemy is cutting off the heads of Christians and drowning them in cages, and yet we are too politically correct to respond in kind,” he wrote in a letter to USA Today in February explaining his support for torture.

“We have to fight so viciously and violently because we’re dealing with violent people,” he said in a June speech endorsing waterboarding that also referenced ISIS executions.

Trump has made this willingness to out-brutalize opponents a central point of his political message. It was an effective strategy during the Republican primary campaign, when his rivals were largely uncomfortable straying from constitutional limits or traditional assumptions of human decency.