CIUDAD JUÁREZ, Mexico — More than 2,500 Mexican troops, from the states of Tlaxcala, Durango, Yucatán and Mexico City, have fanned out along this historically violent border city in a show of force. 

The troops are part of Mexican President Claudia Sheinbaum’s attempt to stave off President Donald Trump’s executive order announcing tariffs on Mexican, Canadian and Chinese goods coming to the U.S., a move aimed at pressuring the three countries into stopping the flow of fentanyl and…