Donald Trump keeps yapping about that wall.

The government shut down for three days over immigration and budget disputes. Then it reopened, with the threat of another shutdown looming in just a couple of weeks.

We’re still trying to hammer out a deal on immigration. But the president wants $20 billion of U.S. taxpayer money to start building the wall along our southern border. Is it an actual wall or a figurative wall?

My question — as always — is simply this: What about that campaign boast that Trump was going to make Mexico pay for the wall?

He blamed Mexico for “sending rapists, drug dealers, criminals” across the border. “I’m sure some are good people, too,” he added, as if to soften the harshness of his tone.

Mexico’s government, of course, said it won’t pay a nickel for the wall. I don’t blame them for digging in on that one. No head of state should dictate to another government how to spend its money.

The wall is a nutty, un-American and patently ridiculous notion. I don’t object to increased border security and better enforcement of existing immigration laws.

The president expended a lot of bluster and bellicosity while campaigning for the office he won by declaring Mexico would foot the bill for a “big, beautiful wall.” It wasn’t supposed to cost Americans anything.

What gives, Mr. President?