Is ISIS using Donald Trump to recruit?

In tonight’s debate, Hillary Clinton said that Donald Trump is “becoming ISIS’s best recruiter” and that the terrorist organization is using the Republican candidate in videos. 

It was a good line, but is it true? It was met with questions and incredulity on Twitter.

J.M. Berger, the co-author (with Jessica Stern) of the excellent ISIS: The State of Terror, is doubtful. Asked by Vox’s Zack Beauchamp if Clinton’s claims were true, he had this to say: