How much convincing does he need?
If you do a Google Search on his name and select the option “Latest”, you’ll see that almost every second someone posts something on the Internet, many of them just voicing their disgust with the plan. And Hillary Clinton and General David Petraeus already voiced her concerns. Also lets not forget the FBI memo.
Or does he want to convince them? After all, he already demonstrated his persuasion power in the past.