“Stephen Miller’s White House will test Mexico’s red lines,” written by Gladys McCormick, Jay and Debe Moskowitz Endowed Chair in Mexico-U.S. Relations, was published in The Hill. Following is an excerpt:

[Stephen] Miller has not been shy about how he sees the problem. At the Pentagon’s counter-cartel conference in Miami this past March, he called the cartels “the ISIS and al Qaeda of this hemisphere” and said they should be met with hard power and lethal force rather than criminal justice.

That describes a policy already in place: eight Mexican criminal groups designated foreign terrorist organizations since February 2025, ongoing lethal strikes on suspected drug boatssince September 2025, and around 500 troops sent to the Texas border this fall after an alleged shooting. As deputy chief of staff, Miller helped shape these decisions. As chief of staff, he controls who reaches the president and what lands on his desk. The officials who counseled patience with Mexico, if any remain, now have fewer ways in. 

A Democratic Congress and the Republicans losses of so many elected positions across border states will not change this. If anything, Miller will push the White House toward the tools it controls alone: terrorist designations, Treasury sanctions, indictments, troop deployments and covert actions.

Unless Congress stops him, Miller will encourage Trump to continue using the cudgel of tariffs to exact concessions from President Claudia Sheinbaum. All of these are exactly the tools that reach into Mexico and weaken her presidency.