Sen. Tim Johnson says he favors a public health care option based on Medicare, the government program for the elderly, or the federal employees' insurance plan.

The South Dakota Democrat says that would enable the government to negotiate lower health care costs with insurance companies.

Johnson says he's also willing to look at a health cooperative proposal. Sen. Kent Conrad, a North Dakota Democrat, has been a leading advocate for consumer-owned nonprofit co-ops that would sell insurance in competition with private industry, not unlike the way electric and agriculture co-ops operate.

Johnson says he has no immediate plans to hold town hall discussions on the issue or participate in them. He says protesters that have disrupted other such forums aren't interested in answers.

Johnson says he's already been called a "Nazi" for supporting health care reform.