Burgess suggested that Congress use that skepticism to take steps to reform Medicare now, without waiting for a final ruling.

"You know, if we were smart, this skepticism could open the way for thoughtful alternatives by this Congress," he said.

Burgess suggested starting with the House Republican budget, which the GOP says would preserve Medicare by finding billions of dollars in savings, raising eligibility to age 67 over the next few decades and linking Medicare spending increases to inflation.

The Republican budget and several alternatives were expected to be debated on Wednesday, and final passage of the preferred GOP budget is expected Thursday.