Feb. 27--On May 10, 2011, President Obama gave a speech near El Paso that turned out to be prophetic.
A border fence stretched for hundreds of miles between the United States and Mexico. The number of Border Patrol agents had doubled to 20,000 in less than a decade. Drones patrolled the skies.
But Obama warned it probably wouldn't be enough to satisfy Republican adversaries.
"You know, they said we needed to triple the Border Patrol," Obama said. "Or now they're going to say we need to quadruple the Border Patrol. Or they'll want a higher fence. Maybe they'll need a moat. Maybe they want alligators in the moat. They'll never be satisfied."
In the 2016 presidential campaign, Republican front-runner Donald Trump has based much of his candidacy on just such a promise to go further -- and to build "the greatest wall you've ever seen" between the U.S. and Mexico.
"I want it to be so beautiful because maybe someday they're going to call it the Trump wall," Trump said in August. Perhaps even bolder was his demand that Mexico fund it, prompting former Mexican President Vicente Fox to say this week, "I'm not going to pay for that ... wall."
But controversies over how to guard the U.S.-Mexico border are as old as the border itself.
