What policy did most americans embrace immediately following wwi?

Isolationist policy.

When the war ended in 1918, the United States returned to its Isolationist policy and renounced to its alliance with Europe, even enacting restriction to limit its immigration, and refused to join the league of Nations, an international organization, first proposed for the current American President Wilson.

Instead, The United States intended to focus more on domestic issues, by supporting business growth, promoting industrial expansion, imposing tariffs on imported products, etc.

the lowest among the social higher rank were the working class. this class remained detached to the political progression   of the country and was hostile to the other two classes