Make him wait till after the tariffs have been in effect a few working days. My guess is most people still do not believe the president will actually do as he threatens to do.
The Cavarans, aided and abetted by the Mexicans have largely ignored statements of Pres. Trump.
Apply 5% tariff.
Review Mexico’s plan(s) to halt illegal crossings.
Quantify drastic reduction in illegal crossings for several months.
Only then pull the tariff.
If illegal crossings thereafter increase by more than x%, there’s a 10% tariff for 6 months, and crossings must decrease.
Rinse and repeat with 15% next time.