Now that it's clear Donald Trump is losing, Mr. Trump has taken to attacking the election process itself. Although the election is nearly 3 months away "The Donald" has decided the entire electoral process, which has elected just as many Republicans as Democrats is "rigged against him" Donald Trump has no evidence of this whatsoever, nor has he made an effort to produce any. The general election in America is the most closely watched election in the world. The amount of verified voter fraud is less than 1/10th of 1%, Still, legions of his followers have blindly chosen to believe this nonsense rather than to find out for themselves. Maybe Republicans really are THAT dumb.
Donald Trump is wrong. Rigging an election is almost impossible.
Well, it wasn't impossible for the Democratic leadership to rig the nomination process to cheat Sanders out of a fair shot at the nomination, and one of the very important ways the leadership rigged the nomination process was to limit the debates. They did this because they know Hillary is a poor debater. In fact, after each debate during the primaries, Sanders gained on her. Since the Democratic leadership, which would include Obama, had already decided to give the nomination to Clinton, it makes sense that even months ago, regardless of who won the Republican nomination, they would want to protect Clinton from being humiliated in the debates, so it is not difficult to believe they pushed the networks to schedule the debates at times when there would be low viewership.
It is not rigged to the extent the Democratic leadership rigged the nomination process, but we have seen in other countries when the government flexes its muscles to influence the media, it can have a powerful effect on the outcome of an election.