Donald Trump’s habit of slapping down Mexico is feeding nationalist sentiment in the country’s presidential election campaign, prompting contenders to defy him and strengthening the hand of the frontrunner, who is courting the anti-establishment vote.
In the past week, the three top contenders for the July election have all said Mexico will not pay for the wall the U.S. president wants to build on the U.S. southern border. None has made the point more forcefully than Andres Manuel Lopez Obrador, a veteran leftist leading the opinion polls.
A victory for Lopez Obrador, who was runner . . .
