Why Is Trump Saying the Election Is Rigged?

RUSH:  Trump is being hit from all sides on this one by even some of his supporters who are upset that he sounds like he's making an excuse already here in August for losing, and then others who claim to be Trump supporters are also saying, "You don't do this.  In the freest nation on earth, you don't tell voters that the entire institution of the presidential election is corrupt and unsalvageable." So this constitutes, in my mind, Trump shifting from an aggressive offensive