Two Mexican opposition candidates on Sunday vowed to take a tougher line against U.S. President Donald Trump’s border wall, at events where they were selected by their parties to seek the presidency in a July 1 election. Andres Manuel Lopez Obrador, 64, of the leftist Morena party holds a double-digit lead in recent polls although right-left coalition leader Ricardo Anaya has recently gained traction. Former finance minister Jose Antonio Meade, 48, nominated on Sunday by the ruling Institutional Revolutionary Party (PRI), trails behind Lopez Obrador by as much as 20 points. Lopez Obrador told several hundred Morena supporters gathered at...