How did the policies of the American government encourage isolationism in the 1920s?

After World War One, America started to isolate themselves from the rest of the world in various ways; refusing to join the League of Nations, rejecting the Treaty of Versailles, tariff polices and immigration control. They refused to the join the League of Nations simply because; most of the American population was made up of people from all different countries and nationalities, therefore it wouldn’t be fair if America started choosing sides with other countries.

German-Americans strongly opposed of the Treaty of Versailles so America decided they didn’t want to be apart of it anymore.

President Woodrow Wilson believed in low tariffs, he had reduced them in 1913 and refused to increase them. Demand was growing, however, for higher tariffs. When Warren Harding became President, he passed an Emergency Tariff, in May 1921, to raise tax on food imports; which led to the Congress passing the Fordney McCumber Tariff in 1922.

The League of Nations: A Pictorial Summary, Geneva...

President Woodrow Wilson asking Congress to declar...

President Wilson before Congress, announcing the b...

The Fordney McCumber Tariff, meant that non-American products were always much more expensive than American products; encouraging the public to buy products from America and resulting in the increase of their independence from the rest of the world.

In 1929, the Hawley-Smoot Tariff raised tariffs to their highest levels in US history. Its supporters, including President Hoover, believed that the high tariffs would help American industry and agriculture in a time of severe depression. In fact, the opposite occurred. As the United States was a net exporter of both agricultural goods and industrial products, the ensuing worldwide tariff war simply lengthened the depression.

In 1924, President Coolidge’s taxation policy was that taxes should be lower and fewer people should have to pay them. The Congress agreed, and the tax burden on Americans was reduced in Coolidge's term. Those with $1 million incomes had their taxes reduced from $600,000...