Renowned economist Paul Krugman on Wednesday poured ice-cold water on Donald Trump’s threat and demand to cut off all U.S. trade with traditional ally Spain, calling it “completely crazy.”

Watch the full analysis on Substack.

Trump fumed about the European country during the NATO summit in Ankara, Turkey, saying it was a “wasted cause” and “terrible partner in NATO.”

The president has previously slammed Spain’s refusal to increase defense spending to 5% of its economic output and for refusing to allow the U.S. to use its jointly-operated air bases for his Iran war.

But the cutting off of trade “is not going to happen,” declared Krugman, the winner of the 2008 Nobel Memorial Prize in Economic Sciences, in a video shared on Substack.

Krugman, a vocal critic of Trump’s economic policies, acknowledged that presidents “have a lot of discretionary authority on tariffs and trade, more than they should” but said this particular move “would not fly even in the Trump administration.”

A bigger spoke in the wheel is that Spain is part of the European Union, which the U.S. deals with instead of individual E.U. member states, Krugman noted. He pointed out that the U.S. has a trade surplus with Spain “so U.S. business would be howling” at the move.