As President George W. Bush and his supporters take their case for Social Security reform on the road, the real 800-pound guerilla in the federal budget seems to have slipped beneath their radar.

Last week, the trustees for Social Security and Medicare presented Congress with their annual report on the long-term outlook of the programs. While noting the future of Social Security continues to worsen, the trustees reminded Congress that Medicare presents a far more urgent challenge to policymakers. That finding gives the Bush administration a golden opportunity to shift its reformist zeal away from Social Security and toward meaningful Medicare reform.

This is not a new idea. Democrats in Congress have consistently argued fixing Medicare should take precedence over partially privatizing Social Security. The trustees themselves made the same recommendation in the report.

Medicare’s predicament should surprise no one. Nationwide, health-care spending has skyrocketed in recent years, with Medicare costs leading the way. As the new prescription drug bill takes effect and the baby boom generation inches closer to retirement, Medicare will consume an increasing percentage of the federal budget. Without serious changes, the trustees expect annual Medicare spending to approach a staggering 14 percent of the gross domestic product during the next 75 years.

The Medicare crisis will be felt sooner. The trustees predict the hospital insurance trust fund to run dry by 2020, leaving policy-makers with a choice between hiking payroll taxes, curtailing benefits or both. Outpatient and physician services face the same pressures. Premiums for those services increased 17 percent last year and are expected to increase 12 percent this year.

There is no denying Social Security demands timely and effective reform. But while Social Security will maintain its reserve until 2041, the Medicare challenge is likely to reach crisis proportions far sooner. That’s because health-care costs are increasing faster than the wages that ultimately fund the Social Security trust fund. Public opinion polls consistently show lackluster support for partially privatizing Social Security. Combine that with the latest trustees report, and the case for moving on to Medicare reform is clear.