Federal Judge Jon S. Tigar of the U.S. District Court for the Northern District of California, a Barack Obama appointee, blocked President Donald Trump’s new asylum policy on Monday night.

On Nov. 9, two days after the midterm election, the president issued a proclamation in response to the “caravan” of thousands of migrants traveling from Central America across Mexico to claim asylum in the U.S. (The date is notable, since Trump’s critics claims his concerns about the caravan were merely an election ploy.)

In the proclamation, Trump said that his administration would no longer honor requests for political asylum unless migrants entered the U.S. legally, through a port of entry:

Crossing the border to avoid detection and then, if apprehended, claiming a fear of persecution is in too many instances an avenue to near-automatic release into the interior of the United States. … I am similarly acting to suspend, for a limited period, the entry of certain aliens in order to address the problem of large numbers of aliens traveling through Mexico to enter our country unlawfully or without proper documentation. I am tailoring the suspension to channel these aliens to ports of entry, so that, if they enter the United States, they do so in an orderly and controlled manner instead of unlawfully. Under this suspension, aliens entering through the southern border, even those without proper documentation, may, consistent with this proclamation, avail themselves of our asylum system, provided that they properly present themselves for inspection at a port of entry. … But aliens who enter the United States unlawfully through the southern border in contravention of this proclamation will be ineligible to be granted asylum under the regulation promulgated by the Attorney General and the Secretary of Homeland Security that became effective earlier today. Those aliens may, however, still seek other forms of protection from persecution or torture.

The proclamation created what was possibly the most effective deterrent to illegal crossings — more so than troops deployed along the border, or even a wall, because neither of those two deterrents could stop a migrant from claiming the legal right to stay in the country pending the adjudication of an asylum request.

But Judge Tigar issued a temporary restraining order, valid until Dec. 19, blocking the administration from implementing Trump’s new policy, saying it conflicted with existing immigration law.

“Whatever the scope of the President’s authority, he may not rewrite the immigration laws to impose a condition that Congress has expressly forbidden,” Tigar reportedly said.

President Obama routinely used — or abused — executive authority to create immigration policies that were against the express intent of Congress, most notably in the Deferred Action for Childhood Arrivals (DACA) program.

The Trump administration canceled that policy, but its cancelation was likewise blocked by the courts and is still pending final adjudication.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.