The public plan -- which is really three, or maybe four, insurance plans -- pays Medicare rates to hospitals (and Medicare rates plus five percent to physicians -- thanks to Marci Wheeler for the correction) for the first three years and then begins negotiating on its own. It is open to anyone with access to the Health Insurance Exchange.

So, who has access to the Health Insurance Exchange, you ask?  Ezra answers:

It's run nationally, though states can opt out of the national structure and go it alone if they choose, and if they follow federal rules. In the first year, it accepts those without health insurance, those who are buying health insurance on their own, and small businesses with fewer than 10 people. In the second year, it accepts small businesses with fewer than 20 people. After that, "larger employers as permitted by the Commissioner." In other words, expansion is discretionary, not mandated. The only people able to access the public plan in the early years will be on the exchange, and the exchange will be, relative to the population, pretty limited. So the public plan will be limited, and so too will any anticipated savings.

In other words, it's not a public option at all, because a large majority of Americans, including most employed healthy adult Americans, do not have the option to use it.

Ezra writes:

Within the Health Insurance Exchange, the basic plan that everyone needs to offer is, well, the "basic plan." On first glance, it's pretty comprehensive: It has to be equal in value to the prevailing employer-based insurance in the area. Cost-sharing cannot exceed $5,000 for individuals or $10,000 for families in the first year (it can then grow by the rate of inflation each year after that). It is heavily regulated. And then there is an "enhanced" plan above it, with less cost-sharing, and then a "premium" plan above that, with even less cost sharing, and then a "premium-plus" plan above that. Of these, only the "premium-plus" plan can vary in benefits, as opposed to vary in cost-sharing. The public plan can offer all levels of plan.

Okay - who, exactly, is sharing the costs?  Less cost-sharing, the better the plan equals, what?  Higher cost to the individual?  And that cannot exceed $5,000 in the first year for individuals?  Maybe I put too much vodka in the vodka-and-tonic tonight, but I don't understand why the public option cannot offer the same coverage to everyone.  Medicare offers the same coverage to everyone - why can't the public option do that, too?  And, like Medicare, people could buy supplemental coverage to fill in the gaps.  As I see it, the public option is looking a whole lot like what the insurance choices have always looked like - and that isn't really my definition of reform.