The Republican Party before World War II was dominated by America First Isolationism, led by Ohio Senator Robert Taft, “Mr Conservative Republican”, and Michigan Senator Arthur Vandenberg.
However, Vandenberg abandoned isolationism with the beginning of the Cold War with the Soviet Union after World War II, but with Taft still pursuing isolationism.
But in 1952, when Taft sought the Presidency, he was stopped by World War II hero Dwight D. Eisenhower, who was able to shift American foreign policy to support of the international community, including support of the North Atlantic Treaty Organization and commitment to fighting Communist expansion around the world.
The majority of Republicans who pursued bipartisanship in foreign policy continued, and reached a new peak under Ronald Reagan in the 1980s, and with the Presidencies of George H. W. Bush and George W. Bush.
However, the wars in Iraq and Afghanistan provoked the emergence of a strong opposition to the policy of interventionism, and also led to those who started to see the Russian Federation that followed the downfall of the Soviet Union in 1991 as not a nation to be seen as “the enemy”.
Donald Trump became the leader of the attack on the interventionist past of the Republican Party from 1952-2016. Now, many Republicans in Congress back Trump on his isolationist bent, including his Vice Presidential running mate, JD Vance.
This is a dangerous trend, and cozying up to Vladimir Putin and the Russian Federation with their war in Ukraine is an alarm bell in the middle of the night, as accepting authoritarianism is a trend toward Fascism!