If Senator (and later President) Harding's speech is an indicator of American feelings in 1920, America was feeling exhausted after the events of the 1910s.
The 1910s had been a decade of upheaval. There was, of course, the tremendous stress of World War I. There were also lesser stresses from the Progressive Movement's pushes for reform. Prohibition had just been instituted. Women had gotten the vote. Many other reforms had been implemented.
From Harding's speech, we get the idea that Americans were tired of all of this. They were tired of the changes that were occurring in their society. They wanted to have some time where no one was trying to fix the world, either through war or through progressive reforms.
It is for this reason that Harding said that it was time for
... not surgery, but serenity; not the dramatic, but the dispassionate; not experiment, but equipoise...