Why did they call the time between 1920-1941 the age of isolationism for the us

United States made little to no business or interaction with Europe

Explanation:

1920-1941 were the years United States mostly kept to itself. The government refused to go into any European conflicts. That changed with the start of World War 2 in 1941 when the Japanese Airforce bombed the American Pacific Naval Base Pearl Harbor sinking USS Arizona, USS Oklahoma, USS Nevada, USS California, USS West Virginia, USS Cassin, USS Downes, USS Oglala and several other ships. In total 18 ships were sunk and 2,403 Americans were killed and 1,143 were wounded