If they start traveling through Meh-e-coh, Trump should shut down the border - no goods or services crossing the border bridges. Two or three days without a major part of their national income shut off will inspire them to take action. Remember that the new president of the country is not a flaming nut case like the previous two.
Also, don’t allow monies accrued in the U.S. to be sent to Mexico via banks.
Close the border and stop all mony transactions until they turn around. Tomorrow stop all flights in or out of Mexico.
Next day, time to revisit that NAFTA agreement again.
Military on he border come Monday morning.