Trump's border wall plan is unrealistic and useless, experts say

Even as Donald Trump vacillates between toning down his harsh anti-immigrant rhetoric and reaching out to minorities, he remains unshakable on one central campaign promise: building a wall on America's southern border with Mexico. "We are going to build a great border wall to stop illegal immigration, to stop the gangs and the violence, and to stop the drugs from pouring into our communities," the Republican presidential candidate said as he accepted his party's nomination last month. "Mexico!"