It’s not often that a single member of Congress generates as much media interest and debate as Wisconsin representative Paul Ryan has with “A Roadmap for America’s Future.” But, given the document’s focus and the political moment, the attention is entirely understandable. This is truly a case of a man with a plan in the right place at the right time.

The most serious medium- and long-term economic challenge our nation faces is that the federal government has committed itself to spending far more than it can collect in taxes. Most of this excessive commitment is in the area of entitlements. Social Security, Medicare, and Medicaid are already expensive — their combined cost to the federal government is expected to hit 9.8 percent of GDP in 2010. But they are set to become simply unaffordable in coming years with the retirement of the baby-boom generation and the continued rapid escalation of health-care costs. By 2030, federal spending on the Big Three is expected to reach 14.4 percent of GDP, according to the Congressional Budget Office.

When this explosion in entitlement spending occurs, the federal budget will already be badly out of balance. The Obama administration is planning to run budget deficits of $1.6 trillion this year and $1.3 trillion next year. (From 1789 through 2008, the federal government borrowed $5.8 trillion total.) Much of this spending is in response to the fiscal crisis, but if it continues, federal borrowing will exceed $18 trillion by 2020, with $1 trillion–plus budget deficits piling more debt on top every year thereafter.