It's possible that the mainstream media are hearing footsteps behind them

When Chris Cillizza writes about Donald Trump like this in the Washington Post, it tells you that something is up.

“I am not a politician,” Trump said. "My only special interest is you, the American people. The guiding rule of the political class in Washington, D.C., is that they are looking out only for themselves. They will say anything, and do anything, to cling to their power and prestige at your expense. I’m running to change and reverse decades of failure, and to work with the American people to create generations of success.”

That is an absolutely perfect message for this I'm-mad-as-hell-and-I'm-not-going-to-take-it-anymore electorate. People want change desperately. And almost no one believes Clinton represents that radical change — or anything close to it. Trump, in that passage above, puts his life outside of politics forward as incontrovertible evidence that he will walk the walk when it comes to bringing real change to the nation's capitol.