If there is anyone who can bridge the gap between the two parties on overhauling entitlement programs such as Medicare and Medicaid, it may be economist Alice M. Rivlin.

During a career spent deep in the numbers of federal budgeting, she has worked as director of the White House Office of Management and Budget for President Bill Clinton, was founding director of the Congressional Budget Office and collaborated with House Budget Chairman Paul D. Ryan, R-Wis., on a Medicare plan that has been as vilified by Democrats as it has been praised by Republicans.

Almost alone among Democrats, Rivlin has championed the idea of injecting competition into Medicare, and thus bringing down its costs, by letting private insurance plans compete for customers on an exchange. At the same time, she is a strong supporter of the 2010 health care law, which she believes offers a slew of ideas that could slow the growth of health care spending in the future.

Where others see differences, Rivlin seeks and often finds common cause.

In the debt reduction framework that she put forward with former Sen. Pete V. Domenici, a New Mexico Republican, the regulation-centered approach to restraining health care costs favored by Democrats is combined with the competition-oriented model promoted by Republicans. “So it’s not saying that either one by itself is a failure,” she said. “But there is a great deal of uncertainty. And the proposal is try both.”

Standing between one side that emphasizes raising taxes and another that stresses cutting entitlement program costs, Rivlin stands out for her steady insistence that both are necessary. “You can’t solve this problem unless you slow the rate of growth of entitlements over the longer term, but especially the two big health entitlements,” she said. “It’s really Medicare and Medicaid, and principally Medicare. That’s a necessary ingredient. And so is tax reform that produces more revenue. They’re both extremely difficult, and both have to be done to get a solution that stabilizes the debt.”

Rivlin could have retired from a distinguished career many years ago. After her tour in the Clinton administration, she went to the Federal Reserve as a vice chairwoman in the late 1990s. She was named one of the greatest public servants of the past 25 years by the Council for Excellence in Government in 2008. President Barack Obama tapped her to serve on his fiscal commission in 2010.

But instead of taking it easy, Rivlin, who received her Ph.D. in economics from Harvard’s Radcliffe College, has continued to play a prominent role in the fiscal and health care debate as a senior fellow at the Brookings Institution, co-chairwoman of the Bipartisan Policy Center’s Debt Reduction Task Force, author and teacher.

What keeps her in the game?

“It’s very exciting and very interesting, and I’m enjoying it,” she said. “I’ve enjoyed being part of public policy for a long time.”