It's frankly a little silly. The epitome of low hanging fruit.
Also he cant help himself and lies about Trump telling the NYT that he "wouldnt build the wall." He said that some things are open to compromise or negotiation.
Frankly this would have been unnecessary as he could have won without needing to. Just shows why people dont like him.
https://www.youtube.com/watch?v=mvzcX4GQEHY