I was reading a dire article in the Wall Street Journal which had almost nothing to commend it, bar being about the 1930s in the USA, which is a period in which I take an interest. But then I noticed this:
After all, the argument of markets has its own powerful morality. It is immoral to cause unemployment by pretending that a big government policy is morally necessary. When Andrew Mellon and Calvin Coolidge put through their tax cuts in the 1920s, they made the efficiency argument that supply-siders make today: lower rates could yield, they posited, higher revenues. But they also had a moral argument: high taxes were wrong, confiscatory and illiberal, in the classical sense.
Funny how supply siders and professionals can use morality to justify low tax when it suits them, and yet claim morality has no place in the application of tax law.
You can't have it both ways.
It's also a fact that supply side arguments do not work, so morality need not come into the argument about the tax revenues these ideas can generate. But on this occasion, that is a side issue.