Yet like the Warren plan, the various Ryan plans were full of questionable assumptions, such as assuming tax revenue would stay steady despite big tax cuts. Or that radical Medicare and Medicaid reform could really put our fiscal house in order. Still, when Ryan first presented his plan to conservative activists, they saw it as a doable roadmap to much smaller government. Progressives, on the other hand, see the unrealistic Warren plan as a doable roadmap to much bigger government.

But neither are doable roadmaps, really. Instead, they are political documents, both aspirational and ideological. And the math doesn’t work in either. Yet Ryan ended his political career assailed by Democrats as a policy phony and fiscal flim-flam man. It’s unlikely any Democrats anywhere will characterize Warren similarly.

Still, both plans serve a useful policy purpose, if inadvertently, by skirting the same issue. To avoid running a dangerous experiment in fiscal irresponsibility, the future federal tax burden will need to be higher than it is today — even without a massive health-care expansion.