Why was the idea of american government intervention undermined in the 1970s?

The idea of American government intervention was undermined in the 1970s due to the Vietnam War that was concluded in 1975 and the result  of war did not favor the USA.

Explanation:

Vietnam was sawed many soldiers die, and several of them went missing. Millions of Vietnamese had died. The US spent over 160 billion during the war.

The US oil management remained mostly in place, however; the "federal government" and the "regulatory agencies" helped in setting oil prices that kept controlling the "imports" as well as domestic production management.

the correct answer is d

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