“The once-unthinkable prospect of U.S. military action on Mexican soil is dominating the political conversation in Mexico as the country braces for President-elect Donald Trump’s second term,” the Wall Street Journal reports. “With Trump and his allies this year floating the use of American military force against Mexico’s drug cartels, Mexican officials have tried to learn whether he is serious or merely blustering to gain leverage in talks about shutting down the pipeline of migrants and drugs heading into the U.S.