Known as an immigration “reformer” Larry Kudlow’s column in National Review Friday took many by surprise. Surprise was expected as the headline makes abruptly clear, “I’ve Changed. This Is War. Seal the Borders. Stop the visas.”

Kudlow begins:

I know this is not my usual position. But this is a war. Therefore I have come to believe there should be no immigration or visa waivers until the U.S. adopts a completely new system to stop radical Islamic terrorists from entering the country. A wartime lockdown. And a big change in my thinking.

Islamic & Communist Supremacists agree on one world with no borders – disagree only on who will be in charge.

ISIS and related Islamic terrorists are already here. More are coming. We must stop them.

Until FBI director James Comey gives us the green light, I say seal the borders.

Here’s what we must do: Completely reform the vetting process for immigrants and foreign visitors. Change the screening process. Come up with a new visa-application review process. Stop this nonsense of marriage-visa fraud. And in the meantime, seal the borders. I agree with Jessica Vaughn, director of policy studies at the Center for Immigration Studies, who argued many of these points in excellent detail on the National Review website on Friday.

Again, why am I taking this hardline position? In the past I have been an immigration reformer, not a restrictionist. But we are at war. That changes everything.

Let me emphasize that my support for wartime immigration restrictions is not based on religion. I think Donald Trump made a big mistake here. Instead, I agree with this Rupert Murdoch tweet: “Complete refugee pause to fix vetting makes sense.”

Fortunately, the Republican House voted to tighten restrictions on travel to the U.S. by citizens of 38 nations who presently enter our country without a visa. This covers 20 million visitors a year who are allowed to stay 90 days. And of course this system is abused, big time.

But I say seal the borders. People hoping to relocate to the U.S. from Syria, Iraq, and anywhere in the Middle East, and people coming here from France, England, Sweden, and wherever will be upset, at least for a while. There may be some unfairness to this. But I don’t care. Wars breed unfairness, just as they breed collateral damage.

Of course, President Obama doesn’t get it. He never will. Already we should have led NATO into a declaration of war against ISIS. Already we should have pushed a resolution of war against ISIS through the UN Security Council. Already we should have convened meetings with our Mideast allies to formally declare war against ISIS. Already the U.S. Congress should have issued a formal declaration of war against ISIS.

Click here for more of this column on National Review.

Kudlow is an American economist, television personality, and newspaper columnist.