NEW YORK TIMES – It has been just over a week since President Trump took office, and he already has a diplomatic mini-crisis on his hands.

First, he demanded that Mexico pay for his wall along our mutual border – on the very day when Mexican diplomats were to meet with White House officials.

When President Enrique Peña Nieto of Mexico rejected that idea out of hand, Mr. Trump tweeted that he should consider calling off a planned visit to Washington next Tuesday. Which is just what Mr. Peña Nieto did.

For Mexico, the cancellation, and the rise in tensions with the United States, are a sad and serious affair.

Editor’s Note: Jorge G. Castañeda was Mexico’s foreign minister from 2000 to 2003. He is now a professor at New York University. To read his op-ed, titled Mexico’s Forceful Resistance, in The New York Times in full, click here.