Karen Davenport is director of health policy at the Center for American Progress, a liberal think tank.

Health-care reform has returned to the top of the political agenda. Americans cite health-care costs and coverage as their most pressing domestic concerns, and many presidential candidates have made affordable coverage for all Americans a top issue in their campaigns.

Today, as almost 45 million Americans go without health insurance, the public sector plays a major role in our health-care system. It provides health coverage to more than 80 million Americans through Medicare, Medicaid, the State Children's Health Insurance Program and other public health programs. The public sector pays for 39 percent of our health spending, and it supports providers who serve low-income populations. Government regulators also protect consumers' rights to buy and use health coverage, and work to ensure that hospitals, nursing homes, laboratories, and other providers meet quality and safety standards.

As we look to expand health coverage, government will continue to play an important role. Today's system is a hybrid of public and private coverage options, and tomorrow's reforms are likely to strike a similar balance.

We can look to past successes to see how the public sector has established new coverage opportunities and provided financial help to those who cannot afford coverage. These include federal efforts such as Medicare, Medicaid and SCHIP, or state programs like the Washington Basic Health Plan, which helps low-income adults buy private coverage, and Insure Montana, which enables uninsured small businesses to buy coverage through a state-run pool. Meaningful change will require building on these options by expanding existing programs such as Medicaid or SCHIP. It will also mean creating new opportunities, such as a national purchasing pool or a public plan option like John Edwards' proposal, and targeting financial aid so everyone can afford health insurance.

Public efforts can also improve our collective health in ways that individual insurers and providers simply cannot manage. For example, it is in everybody's interest to make preventive care a national priority; our shared costs will decrease, while our individual and collective health will improve. We could establish a universal prevention benefit -- a public program that would create a new emphasis on promoting good health. Under this approach, preventive care would be covered as a publicly financed benefit, no matter what insurance each individual holds, and we could receive -- and pay for -- preventive services through schools, workplaces, community centers and other settings, in addition to doctors' offices.

Simply put, the public sector is a big part of our health system today, and it will be tomorrow. As we seek to ensure that all Americans have affordable coverage and better health, we will be making choices about public dollars and public health priorities. Government will provide the structure for these decisions, as well as the initiatives that will help us achieve our goals.

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