President Donald Trump has threatened to immediately double all current U.S. tariffs on Mexico if the country allows a migrant caravan of more than 1,000 people to reach the U.S. border. In a lengthy Truth Social post on Thursday, Trump said the caravans were an "invasion" of the country that had resumed after Republicans suffered losses in the midterm elections, adding that he himself was "NOT ON THE BALLOT." He demanded that Mexico "STOP THEM, NOW," and said the governor of Texas, the Border Patrol and ICE had all been informed that there would be "no leniency."

The group, estimated by Reuters at about 1,500 people and described by S3 as mostly from Central America, set off on Tuesday from Tapachula, a southern Mexican city near the Guatemala border, with the aim of reaching Mexico City, more than 1,000 kilometres away. Reuters reported that many members are families, including parents travelling with young children, and the caravan has been dubbed "God With Us." Some migrants told AFP they were motivated by the prospect of looser U.S. immigration policy after Democrats won control of Congress, with one 47-year-old Nicaraguan, Cesar Sandoval, saying he hoped for "another chance" to enter the United States.S1S2

Analysts have cautioned that major changes to immigration policy are unlikely while Trump remains president. The caravan is the third to attempt the journey through Mexico since September; the two earlier groups were broken up by authorities and their members granted temporary stay permits. Trump has repeatedly used tariffs as a bargaining tool with other countries on immigration, trade and security, a strategy that could matter more as his presidency enters its final phase.S1S2

The political backdrop also includes changes in state law enforcement. The Democratic Texas attorney general-elect, Nathan Johnson, could drop the state's defence of SB4, a Republican-backed law allowing state authorities to arrest and prosecute people suspected of illegally crossing the border, which the Fifth Circuit Court of Appeals allowed to take effect in April. Johnson is due to be sworn in on Jan. 1, 2027. Iowa's Democratic attorney general-elect, Nate Willems, could likewise decline to defend a similar Iowa law if the U.S. Supreme Court agrees to hear that appeal, which it is currently weighing. Florida Attorney General James Uthmeier has argued against loosening enforcement, saying Florida had deported tens of thousands of criminal illegal aliens.S3