Democratic candidates for president gathered last night to debate, and moderators asked, what would you do to address the number of people crossing illegally? The discussion devolved into the question of whether crossing should remain a crime (punishable by prison time) or just a civil infraction (punishable by deportation). No one stated the obvious: that Congress should make it legal, not to trek through Mexico and swim the Rio Grande, but to board private U.S.-bound airplanes and come to the United States to work.

According to the Department of Homeland Security, the average Central American is paying north of $8,000 to make it to the U.S.-Mexico border where they are brutalized in Mexico and in the United States. Round‐​trip airfare from El Salvador, Guatemala, and Honduras is under $300. People are dying on the way to make that illegal crossing. When will politicians step up and say clearly, “We think it should be legal to travel to America.”

Sen. Klobuchar came the closest by arguing for the “the economic imperative” to allow immigrant “workers in our fields and in our factories.” But no one made the explicit connection between the availability of visas—which allow noncitizens to board U.S.-bound flights—and illegal crossings. It is not that the civil v. criminal debate isn’t important. It is. But it ignores everything up to the moment where a father makes a fateful decision to jump into a river and cross illegally.

For nearly a century and a half, it was not illegal to travel to the United States (unless you were Chinese after 1882). Immigration restrictions otherwise exlusively focused on criminals, valid public health concerns, and people likely to end up on public welfare. Cato’s first policy analysis on immigration from 1981 argued that the United States should return to this system. The author wrote, “In all the debate over immigration, no one seems to be considering the possibility of returning to America’s traditional open immigration policy.”

The Democratic candidates’ debate has shown how little has changed. The reality of the matter is this. By the end of 2019, nearly 730,000 immigrants from Central America’s Northern Triangle will enter Border Patrol custody. But the U.S. government will issue fewer than 10,000 work visas to nationals of those countries. This disconnect is the cause of the immigration crisis.

Strangely, former‐​Congressman Beto O’Rourke ended up tacitly defending the continued criminalization of illegal crossing (for anyone except asylum seekers), yet his immigration plan contains the most explicit declaration in support of a free market in international labor. His plan contains a line that states that he would “increase the visa caps so that we match our economic opportunities and needs … to the number of people we allow into this country.” This seems like a round‐​about way of saying: let supply and demand function in international labor markets. Perhaps he forgot about that part.

The government doesn’t even need to issue visas to everyone who could conceivably want to come in order to resolve this problem. It just needs to issue enough visas that people can see that legal immigration is the easier path in the future than crossing illegally. The goal should be to lower the cost of legal immigration to at least the point that it is less costly to follow that path than to come to the border.

In a piece for The Bulwark last month, I argued that the government should charge immigrants a fee that is less than what they would pay to smugglers to allow migrant workers to come to the United States. This is essentially what the folks at IDEAL Immigration have proposed. This would cover any fiscal costs associated with the immigrants’ arrivals, bankrupt smugglers, and cure the illegal immigration problem.

Such a plan would increase revenues. Yet the bipartisan consensus in the House and Senate right now is to spend billions more on the border detention camps. If immigrants had a viable route to come here legally, U.S. taxpayers wouldn’t need to spend billions every year to fund detention camps, nor would immigrant children be forced to go without toothbrushes and soap while detained. How many more dead children will it take to make politicians decide that this is better?