There is, however, one way that a Democrat majority can plausibly bring down inequality: Just let government keep growing.

This is the lesson of Western Europe, where the public sector is larger and the income distribution much more egalitarian. The European experience suggests that specific policy interventions — the shape of the tax code, the design of the education system — may matter less in the long run than the sheer size of the state. If you funnel enough of a nation’s gross domestic product through a bureaucracy, the gap between the upper class and everybody else usually compresses.

But economic growth often compresses along with it. This is already the logic of our current fiscal trajectory: ever-larger government, and ever-slower growth.