MEXICO CITY — Mexican officials are carrying out the Trump administration’s immigration agenda across broad stretches of the border, undercutting the Mexican government’s promises to defend migrants and support their search for a better life...(snip) ...Officials inside the administration of Mexico’s new president, Andrés Manuel López Obrador, have called his stance on migrants a strategic decision not to anger President Trump. He doesn’t believe he can change Mr. Trump’s mind, they contend. Furthermore, the officials say, Mr. López Obrador has not wanted to jeopardize other aspects of the deeply interconnected relationship between the two countries, ranging from elaborate regional trading...