Answer:
The term was publicated by U.S. President Richard Nixon in a televised address/speech on November 3, 1969,(Election day) in which he said, "And so tonight—to you, the great silent majority of my fellow Americans—I ask for your support." He is mentioning the ones who do not gather in large demonstrations (protests,riots,etc.) Similiarly the GOP Candidate (Donald J.Trump) uses the same phrase.
