“The reign of tears is over,” said evangelist Billy Sunday on the day Prohibition was signed into law. “The slums will soon be only a memory. We will turn our prisons into factories and our jails into storehouses and corncribs.”

In March 2010 in the White House East Room, Vice President Joe Biden evangelized in his own way while congratulating Obama on signing his health-care bill into law. He whispered into Obama’s ear that “it’s a big (expletive) deal.”

A lesson about American politics is to be learned here, one that people who live in the moment tend to forget: Political movements are just that ­­— movements, sliding in and out of favor, often without notice.

Some components of these movements last, certainly. Yet, typically, the loudest is the first to go.