It was reinforced with Ronald Reagan. Remember how he spun the Iranian revolution and the bad economy on his opposition? Remember how he rode the Moral Majority wave?
It was taken up a notch by G. W. Bush and his band of trigger-happy self-serving country club elitists.
No one in between those points tried to roll back the progress. They're just as guilty. It's been a monotonic increasing function towards the current apex (nadir?).
Fear what comes next. If there is a next.