Mexico's "cool-headed" approach to U.S. President Donald Trump's tariff offensive has paid off in preferential treatment in his sweeping tariff announcement this week and a close working relationship with his trade team,

The US president has repeatedly threatened the United States' top trading partner with punishing tariffs over illegal migration and drug smuggling. So it was a surprise when he left Mexico off the list of nations on which he imposed levies ranging from 10 to 50 percent.