A lot of conservative Democrats, not to mention Republicans, express two big concerns about health reform. They're worried that reform will cost too much. And they don't want a government-run insurance plan.

It's about to get a lot harder to make those two arguments simultaneously.

According to a pair of Capitol Hill sources, preliminary estimates from the Congressional Budget Office suggest that a strong public option--the kind that the House of Representatives is putting in its reform bill--should net somewhere in the neighborhood of $150 billion in savings over ten years.

The sources cautioned that these were only the preliminary estimates, based on previous discussions--that CBO had not yet issued final scoring on language in the actual bill. But the sources felt the final estimate would likely be close.

Exactly how the plan produces those savings is, obviously, a key question. The reason--well, a reason--centrists and conservatives don't like a public plan is that they fear it will use the government's bargaining leverage to force doctors, hospitals, and drugmakers to accept unfairly low reimbursements. Private insurance would go out of business, since they couldn't compete; meanwhile, providers and producers of medical care would struggle to stay afloat.