Writing in the Wall Street Journal, Congressman Paul Ryan lays out a pathway to facing up to this nation’s unsustainable spending. And he reminds us again why structural spending reforms must be part of any package Congress approves. We’re simply swimming in promises we can’t possibly keep.

If Mr. Obama decides to talk, he’ll find that we actually agree on some things. For example, most of us agree that gradual, structural reforms are better than sudden, arbitrary cuts. For my Democratic colleagues, the discretionary spending levels in the Budget Control Act are a major concern. And the truth is, there’s a better way to cut spending. We could provide relief from the discretionary spending levels in the Budget Control Act in exchange for structural reforms to entitlement programs.

These reforms are vital. Over the next 10 years, the Congressional Budget Office predicts discretionary spending—that is, everything except entitlement programs and debt payments—will grow by $202 billion, or roughly 17%. Meanwhile, mandatory spending—which mostly consists of funding for Medicare, Medicaid and Social Security—will grow by $1.6 trillion, or roughly 79%. The 2011 Budget Control Act largely ignored entitlement spending. But that is the nation’s biggest challenge.

Unbelievable — 79% growth in mandatory spending over the next 10 years.