Donald Trump released an immigration reform plan on Sunday with three “core principles,” the first of which is utterly unrealistic: to make Mexico, a country mired in corruption scandals, pay for a border wall. If the next president decides America needs a wall along the entire southern border, he or she will have to find a way for America to cover the cost. Same goes for just about everything else in Trump's incredibly costly plan.

"A nation without borders is not a nation," Trump's plan declares. "There must be a wall across the southern border." He bemoans illegal immigration's "extraordinary" costs to taxpayers, but as CNN estimated in July, the cost of erecting a wall would be close to $20 billion—before factoring in maintenance and staffing. "I think that it's possible," Marc Rosenblum, the deputy director for the U.S. Immigration Policy Program at the Migration Policy Institute, told the network, "but it would prove to be extraordinarily expensive."

The second principle, “Defend The Laws And Constitution Of The United States,” calls for tripling the number of U.S. Immigration and Customs Enforcement (ICE) officers, implementing nationwide e-verify, a “mandatory return of all criminal aliens,” “detention—not catch-and-release,” defunding so-called sanctuary cities, enhancing penalties for overstaying a visa, cooperating with local gang task forces, and ending birthright citizenship. Two of those proposals in particular would have major fiscal and economic consequences:

  • Tripling ICE officers could cost upwards of $15 billion, as the 2015 Department of Homeland Security Appropriations Act already provides $5,932,756,000 for “Salaries and Expenses” for U.S. Immigration and Customs enforcement. (ICE would not provide a cost estimate for this proposal, as the agency's policy is not to comment on proposals made by political candidates.)
  • Withholding federal funding from sanctuaries would impact more than 200 cities, counties, and states. This includes several of the largest cities in the country. New York receives around $6 billion in federal grants or funds per year; San Francisco gets $207 million, Chicago $1.4 billion, and Washington, D.C. $3.2 billion.

Trump wants to deport all “criminal aliens,” but as CNN noted, we already deport immigrants who have been convicted of a felony. Of the 102,224 immigrants deported in 2015, “86,923 (85 percent) of all interior removals involved individuals previously convicted of a crime,” according to an ICE report. However, Trump has also previously said that he supports deporting all estimated 11 million undocumented immigrants currently living in the U.S. and then allowing some to return through an expedited legal immigration process. The Center for American Progress estimated in 2010 that just deporting the 11 million would cost $200 billion—which may be why Trump left it out of his reform plan (for now).

Trump's plan is like Trump himself: audacious, vague, and fiscally reckless. But perhaps the press shouldn't keep him to his word here. He told The Washington Post recently that he doesn’t think voters want to hear policy details. “I think the press is more eager to see it than the voters, to be honest," he said. "When you put out policy, like a 14-point plan? A lot of times in the first hour of negotiation, that 14-point plan goes astray, but you may end up with a better deal. That's the way it works. That's the way really life works. When I do a deal, I don't say, 'Oh, here's 14 points.' I go out and do it."

That approach might work in the real estate world. But it’s hard to believe that Americans—to say nothing of Congress—wouldn't question a program that costs taxpayers tens of billions of dollars.