Ronald Reagan’s famous question that sank Jimmy Carter in 1980 — “Are you better off than you were four years ago?” — could be reprised to measure the performance of Barack Obama and the Democrats. The latest figures from the Census Bureau and Federal Reserve suggest the answer would be an emphatic “no.”

In 2008, Mr. Obama’s message of hope and change resonated with the promise of “policies that invest in our middle-class, create new jobs, and grow this economy from the bottom up so that everyone has a chance to succeed.” Audiences cheered, but now with the knowledge from experience, the question becomes, has that investment paid off?

A new Federal Reserve study finds the median net worth of families last year fell to its lowest level since 1992, after adjusting for inflation. For most families, this means that the work of two decades of economic…