Leftism has been on life support for fifty years. The Republican landslide in the 1966 midterm election was recognized by everyone at the time as a massive rejection of the agenda and the politics of the left.
The reasons were clear. The War on Poverty produced race riots and idiocies like “Welfare Strikes.” Having achieved civil rights, militant blacks were now demanding “Black Power.” Affirmative action was so clearly discrimination that there were few serious minds who could coherently defend this vile incarnation of state-mandated bigotry.
The left’s approach to foreign threats was precisely as it is today: put in our brave men in harm’s way with no discernible purpose other than to make Washington bosses look good; reject waging war to win and instead muddle from failure to failure hoping not to win or to lose; reduce defense spending so that in any future conflict, instead of spending treasure, we would spend blood.