Calvin Coolidge was heir to an attitude of Know Nothingism.
The Immigration Act of 1924 baring Eastern and Southern Europeans (read Catholic) and Japanese sums up the inner Coolidge nicely.
The bigotry he expressed by signing the Act seems to be inculcated in his inner most beliefs.
That same inculcation rears its devilish face in the segregationist attitudes of Gresham Machen.