How many American Jews are there, and does it really matter?

(JNS) — Two weeks ago, the White House Passover seder was hosted by America’s Second Gentleman Doug Emhoff. The Brooklyn, N.Y.-born lawyer is the first Jew to be a spouse of a vice president, as well as the first male to occupy the role. Being a Jew in such an important place in American society is not quite as big a deal as it might have been in previous eras when most Jews were either immigrants or first-generation Americans. Nonetheless, Emhoff has become a symbol of the acceptance of a community that was once marginalized.

The same might also be true for his children, who call his wife, Vi...