The most remarkable thing about this is that it’s happening amid good economic news. It takes a lot of deterrence to keep a would-be illegal from crossing the border with the prospect of a (relatively) high-paying American job on the other side. And Trump wants a lot of deterrence — but most of his wishes are, for now, still wishes. He wants 15,000 more Border Patrol agents and of course a long, long wall (with a big door!), but those goals are still a ways off. And yet, apparently, illegals are staying home anyway. I wonder what sort of rumors are being spread in Mexico about the special new perils of trying to illegally enter Trump’s America. Even with the media attention given to ICE raids over the past two months, the odds of any individual illegal being picked up are vanishingly small, especially a new arrival who’s not on the agency’s radar yet.

Oh well. Whatever works.

John Kelly says in written testimony submitted to a Senate panel that fewer than 12,500 people were caught crossing the border last month. That compares with more than 43,000 who were detained in February. It’s the lowest monthly figure in at least 17 years.

Kelly says the decrease is “no accident” and credits President Donald Trump’s approach to illegal immigration. The Trump administration has not yet changed how the border is patrolled, but the president’s tough talk on immigration and arrests of immigrants living in the country illegally have likely acted as deterrents.

Yeah, it’s probably Trump himself that’s the chief deterrent. The “madman theory” of presidential leadership typically applies to foreign policy, but there may be something to it in immigration too. Illegals may be watching this guy from across the border worrying not that they’ll be deported if they sneak over and get caught but that they’ll be put in prison, labor camps, or lord knows what else. It’s the same fear that seems to have been driving refugees north to Canada, even in the bitter cold of winter.

David Aguilar, former chief of the Border Patrol, also reported an amazing drop in illegal immigration at a Senate hearing today:

Illegal immigration across the U.S.-Mexico border has continued to fall under President Trump, dropping 67 percent through the end of March, the former border commissioner told Congress on Tuesday…

“It’s actually up to 67 percent drop compared to last year,” David V. Aguilar, a former chief of the Border Patrol and former acting commissioner of U.S. Customs and Border Protection, told the Senate Homeland Security Committee…

Mr. Aguilar said these kinds of drops have occurred before, during the Reagan administration, after Congress passed a broad amnesty granting legal status to millions of illegal immigrants, and promised to get tough on enforcement.

Maybe we don’t need a wall at the border. Maybe all we need is a scary photo of Trump every 100 feet or so with a skull-and-bones insignia underneath.

It’s a lot cheaper than a wall. We need a plan B anyway: Given the touchy politics involved, the wall might not get built after all. Exit question: If Trump follows through on his promises to have a “big heart” when it comes to legalizing DREAMers, will that restart the flow at the border by convincing Mexicans that he’s not a madman after all?