Donald Trump spent more than a year rousing crowds with a simple promise: ''I'll build a great, great wall on our southern border, and I will have Mexico pay for that wall.'' As the campaign wore on, it got so he could ask ''Who's gonna pay for the wall?'' and the audience would roar, ''Mexico!''
It was fun while it lasted. But now, in the cold light of day, some facts are coming into focus: It may not exactly be a wall. It won't be paid for by Mexico. And it may not get built.
Interior Secretary Ryan Zinke is one of the people backing off from this promise.
Non-wall options, such as electronic sensors, will have to be considered in some places, he said.
You see, ''the border is complicated, as far as building a physical wall.''
Not only that but where would we locate it? ''The Rio Grande, what side of the river are you going to put the wall?'' Zinke asked. ''We're not going to put it on our side and cede the river to Mexico. And we're probably not going to put it in the middle of the river.'' The Mexicans won't invite us to erect the structure on their side. So siting may be a problem.
That's not all the Mexicans won't do. President Enrique Pena Nieto has said repeatedly and unequivocally that his government will not bear the cost.
Trump had the chance to out-negotiate Pena on the wall when he met with him in Mexico City last summer -- but Trump chose not to even raise the payment issue.
The Mexican president was supposed to come to Washington for a White House meeting in January. But when Trump said it would be better to cancel the trip if Mexico was not willing to pay for the wall, Pena canceled the trip.
Trump said that rather than make Mexico pay for it upfront, ''we'll be reimbursed at a later date from whatever transaction we make from Mexico.''
So we'll send the invoice and they'll mail a check? Well, not exactly.
''There will be a payment,'' he told ABC News. ''It will be in a form, perhaps a complicated form.''
No one on Capitol Hill seems to share Trump's confidence.
When Politico's Jake Sherman asked Mitch McConnell whether Mexico will pay for the wall, the Senate Republican leader couldn't suppress his mirth at the very idea. '''Uh, no,' he shot back, chuckling,'' Politico reported.
House Speaker Paul Ryan said with solemn vagueness, ''We will be working with [Trump] to finance the construction of the physical barrier, including the wall, on the southern border.''
Faced with the funding disagreement with Mexico, Trump included money for the wall in his budget outline, with the funds taken from other programs.
Republican enthusiasm is not abundant. Sen. Cory Gardner of Colorado, head of the National Republican Senatorial Committee, said recently that ''billions of dollars on a wall is not the right way to proceed.''
Sen. Lindsey Graham of South Carolina agreed it is ''probably not a smart investment.''
Democrats have promised to block any bill that includes money for the wall, which means they could force a government shutdown if Republicans attach it to the emergency spending measure that needs to be approved by April 28.
Ryan said recently that the wall appropriation will be dropped to avert a possible shutdown.
But there may not be much interest in funding it afterward, either.
The House Freedom Caucus is generally not fond of spending money, and Trump's declaration of war on the group will not make its members more eager to indulge him.
Plenty of Senate Republicans are also skeptical. ''If you're going to spend that kind of money, you're going to have to show me where you're going to get that money,'' Sen. Lisa Murkowski of Alaska said in February. ''We can't pay for it out of thin air,'' said Sen. James Lankford of Oklahoma.
There don't seem to be many people in Washington who think the wall can be built as Trump claimed or that it would work very well.
Not to mention that it sounded a lot better when Mexico was going to pay for it.
Trump fooled a lot of voters when he made that promise, and he may have even fooled himself. But at some point, you run out of fools.
STEVE CHAPMAN writes for the Chicago Tribune. His column is distributed by Creators Syndicate Inc.