There may have been some sentiment in the pre-W.W. II U.S.A. to stay out of European problems, conflicts and social diseases. Britain after all had burned down the U.S. capital in 1812 and the Franco-Prussian war of 1874 was no great thing.
The United States had numerous post-civil war reconstruction problems. Intervention in the First World War had created much turmoil. The United States had plenty of work to do in its own space such as building, roads, electrification, dams and so forth. It was a busy time of great post-war expansion that became a bubble that crashed leading to the depression.
As Americans had spent money bailing Europe out of the vast diagonal trench war by joining on the pile of soldiers and artillery that forced Germany to accept an armistice and levied a bill for damages on them (that in part was a motivation for the second round) they spent the 1920′s chasing national progress. That was followed by the depression. Some Americans made clothing out of gunnysacks (large burlap bags to hold potatoes) and sought work.
A former French Chancellor- Clemenceau predicted that when the allies did not guarantee the peace after the First War that the second war would develop and he turned out to be right. American investors felt that building up German industrialization perhaps an I.B.M. or Henry Ford are examples. was a better idea than entering into more military agreements.
It is somewhat doubtful that in the 1920s Calvin Coolidge or Herbert Hoover would have had the international political skill and military power (the United States wasn’t yet a Super power militarily and had no A-bomb up its sleeve) to keep Europe pacified while containing the extreme communist threat from the Soviet Union. In fact the Soviet Union’s emergency into existence during the First World War when Germany beat up the Tsar’s military pretty readily leading to the revolution and Red revolution of 1917 gave the United States a fair reason to reinforce Germany on the right to defrappe the Red threat from the east.
I also suspect that the rich of the gilded age were somewhat sympathetic to the deposed German royalty that were booted out in the German revolution at the end of the first war. The United States had actually sent some military forces to support the white army battling the reds during the Russian revolution – about 2000, and that hadn’t worked out well.
In order to keep things strait U.S. politicians developed a long range policy of being against Reds and Russians that continued to the present. That single attitude makes it easier for U.S. leaders to know how to play their roles without knowing much about international affairs.
In my opinion the U.S.A. wasn’t very isolated in the 20s and 30s. Jet aircraft didn’t exist and even Pan Am hadn’t started trans-Atlantic flights. People that had immigrated here or were descended from immigrants usually hadn’t the money to afford to tour Europe via cruise ship and then return home to the little house on the prairie. The rich however did travel to Europe a lot. Franklin D. Roosevelt visited Europe maybe 30 times before he turned 18 and that probably helped him manage the Second World War better than if he had just rowed up and down the Hudson River on some kind of rowing team when not driving a taxi.
One result of the chaos in Europe was the decision to limit immigration from Eastern Europe where it was believed many anarchists lived who might bring anarchy and communism to the U.S.A. Because the rich were running government then, as now, the red danger from Eastern Eurasia decisively prevented some immigrants from spending their lives breathing the air of freedom that exists some places west of the east coast, or did then, before pollution expanded from automobiles a lot in urban areas of the as as far as Los Angeles.