President Claudia Sheinbaum is detaining more migrants, seizing more fentanyl and positioning her country as a key ally against China. But the U.S. stance has shifted, too.

The rush of moves are meant to secure aid for migrants who are facing US President-elect Donald Trump’s promise to carry out “the largest deportation operation” in the nation’s history. The Mexican president’s efforts have taken off in the days and weeks since Trump threatened to impose economically debilitating tariffs on his southern neighbor — the flow of migrants being a bargaining chip,

Now outside a series of north Mexico border crossings where mazes of concrete barriers and thick fencing eventually spill into the United States, hope and excitement evaporated into despair and disbelief moments after President Donald Trump took office.