The other candidates are totally scared shitless of Trump. They don't want to tangle with him and be exposed.
Trump has a 79% disapproval rating among non-whites.
http://www.brookings.edu/research/papers/2013/05/10-election-2012-minority-voter-turnout-freyMinorities are voting more than ever. 2004 to 2012, it's almost a 5 % jump of share total voting.
Trump is going to win the GOP because they vote angry. But when the nation has 9 months to think about what the mass deportation of 20 million people is going to look like lol... FEMA camps, shootouts, a reverse underground railroad... people with medical conditions, orphans, people selling/buying identities... and many other problems we haven't even considered yet. The entire cities that'll be set up right outside the 'wall'. The cost of it all, the disease and crime that these cities of 20 million people will see... MEX doesn't want them, they're not citizens there either.
The ramifications of 20 million people living in the dirt up against the US wall is mind-boggling. Drugs, crime, prostitution, dead body pics getting tweeted daily... catapults sending people and drugs over the wall... blowing holes in the wall... i mean, some of the silly shit that'll happen...
unless it'll never happen, and trump is just bullshitting (my belief) - ESPECIALLY because july 26th, he said they could stay, and 3 days later, they were all getting deported. You don't just change your mind on 20 million people, in 3 days. He did it as a political move.