Sometimes a basic term is misunderstood because everyone assumes its meaning is clear.
Conservatism at root is the desire to conserve the existing order. It’s a natural instinct. “If it ain’t broke, don’t fix it.”
Conservatism as a movement arises when the existing order is attacked by revolutionaries. The revolutionaries believe the old ideas are false and unjust and must be replaced. The conservative knows the existing order is good and tries to protect it.
The American conservative movement became potent in the postwar period. At that time the existing order was being attacked by liberal and leftist revolutionaries. The superstructure of the American order was basically sound although its religious, philosophical and social foundations had been severely weakened. At that time, mainstream American conservatism was about the business of protecting an existing order that was outwardly healthy because its visible structure still reflected traditional ways and beliefs.
Some visionaries understood that the foundation was weak and they called for it to be strengthened. They were mostly ignored. To switch metaphors: heart surgery is dangerous, only to be undertaken when the patient is in imminent danger, and most conservatives believed the patient had only a superficial injury.
The revolutionaries were able to overthrow the old order because of the weakness of its foundations. They have taken control. They are establishing a new order based on revolutionary principles: DIE, BLM, CRT, LGBTQ+,… They do not have total control yet, and counter-revolution is still possible, but the hour is late.
Since the existing order is now revolutionary, the conservative instinct is now to preserve the revolution. That is the fatal flaw of mainstream conservatism: thinking that the existing revolutionary order is good just because it is the existing order. Mainstream conservatism only opposes “extremist” revolution. It supports mainstream, establishment revolution: moderate amounts of feminism, atheism, globalism, immigration, affirmative action, and so on. Mainstream conservatism sometimes makes good-sounding promises, but it does not deliver what is needed.
Within living memory mainstream conservatism opposed the revolution. Conservatives can still be honorable if they work to re-establish the good ways of the old order.