His promise to the American people was that Mexico was going to pay for The Wall. They told Trump to go fuck himself.
So now he is using extortion against the citizens of the United States to pay for his cockamamy idea. "Hey Donny, go fuck yourself you moronic scissorbill!"
From a leaked document, Trump to Pena Nieto,
Quote:
"You cannot say anymore that the United States is going to pay for the wall," he said. "I am just going to say that we are working it out. Believe it or not, this is the least important thing that we are talking about, but politically this might be the most important talk about."