What was the effect of William F. Buckley’s magazine national review?
It helped propagate the Neoconservative ideology.
National Review was created in 1955. The fifties saw the beginning of the Cold War. In the fifties the American Right was split between two sides: on the one hand those who favored internationalism and those who opposed it.
Internationalism meant both military intervention overseas and frontal opposition to Communism. Some eminent members of the Republican Party such as Robert Taft opposed the USA joining NATO.
Isolationism was the original ideological position of the Republican Party and of the American Right. The Cold War convinced most of the party to shift to internationalism. After the Gulf of Tonkin Resolution in 1964, most of the party had shifted to internationalism that is to say to Neo-Conservatism.
William Buckley was one of the most prominent outspoken proponent of that new ideological shift of the Republican Party.