The supplemental premium quickly became an issue as more affluent Medicare beneficiaries got wind of it. Many of those retirees already had some semblance of the new coverage and resented being asked to pay for it for others.

“It blew up,” said Mr. Donnelly, who left the House, served as an ambassador and is now retired. “A lot of people in the United States already had this coverage. Almost every retired union member had the coverage through negotiated benefits.”

In addition, the revenue from the new premium was projected to exceed what was needed and quickly build a surplus, feeding a perception that the catastrophic-care program was a backdoor route to reducing the deficit through a tax on retirees.

To their chagrin, advocates and critics of the measure also discovered that many people who were supposed to be thrilled about the new plan misunderstood it and thought it was going to ease one of their great fears — the expense of living in a nursing home. When consumers came to realize that it did little to help with long-term care, enthusiasm dipped.