Ever since it became clear that the pace of the economic recovery was falling short of expectations, two competing narratives have vied to dominate our politics. Movement conservatives argue that the weight of a government that “spends too much, taxes too much, and borrows too much” is suffocating the private sector and that new laws and regulations have throttled investment and job creation by creating uncertainty about the costs of doing business. Keynesian liberals, meanwhile, counter that the problem is the collapse of demand and that the government’s failure to offer a large enough stimulus is consigning us to a rate of growth not easy to distinguish from stagnation.

What if they’re both wrong? That’s the claim of Amir Sufi, a finance professor at the University of Chicago’s Booth School of Business. The data tell a compelling story, he argues: “The main factor responsible for both the severity of the recession and the subsequent weakness of the economic recovery is the deplorable weakness of the U.S. household balance sheet,” which is, Sufi shows, “in worse condition than at any other point in history since the Great Depression.”

Because Sufi’s argument makes so much intuitive sense, I started digging into the data for myself. And the information I found supports his thesis.

For instance, according to reports issues quarterly by the Federal Reserve Board of New York, household debt rose from $4.6 trillion in 1999 to $12.5 trillion in early 2008. After three years of painful deleveraging (mainly through home foreclosures and reductions in credit card balances), it still stands at $11.5 trillion—roughly where it was at the beginning of 2007.

To understand the burden this imposes on households, let’s look at a key measure: the ratio of household debt to disposable income. Between 1965 and 1984, the ratio remained steady at 64 percent. Between 1985 and 2000, it rose virtually without interruption to 97 percent. And then, it shot into the stratosphere, peaking at 133 percent in 2007. Four years later, according to the Federal Reserve Bank of San Francisco it has come down only modestly: Household debt still stands at 118 percent of disposable income.