It's true that a "strong" public option would be able to offer lower premiums than its private competitors. However, a "weak" public option -- one that competes on a level playing field with private insurers -- probably wouldn't. Here is how the Congressional Budget Office describes that public plan that would be set up under the health care legislation that recently passed the House:
[A] public plan paying negotiated rates would attract a broad network of providers but would typically have premiums that are somewhat higher than the average premiums for the private plans in the exchanges. The rates the public plan pays to providers would, on average, probably be comparable to the rates paid by private insurers participating in the
exchanges. The public plan would have lower administrative costs than those private plans but would probably engage in less management of utilization by its enrollees and attract a less healthy pool of enrollees.
A public plan does not automatically expand coverage. Federal subsidies expand coverage, and those subsidies are not tied to the public option, unless it is a "strong" public option.
Second, it's not clear that a majority of Americans favor the public option. Unfortunately, polling on this subject is very complicated. Some respondents who voice support for the public option probably couldn't tell you what it is. In fact, many Americans cannot even connect the term "public option" to health care. All we can really say for certain is that people respond positively to the word "option," but less positively to terms like "government-run" or "government-controlled" health care.
Third, as Peter Suderman points out, the health care legislation under consideration is unlikely to "reduce" the national debt, as many on the left claim. The CBO (typically) only makes cost projections within a 10-year period, and the spending in this bill is extremely back-loaded.
When the Congressional Budget Office scores a bill, its looks at the budgetary effects over the immediate ten year window. So on the health care bill, the headline cost of $849 billion covers the period between 2010 and 2019. Problem is, it's a misleading figure since most of the new programs don't actually kick in until 2014, and, as a result, most of the spending—99 percent, according to the CBO—doesn't occur until the final six years. That means it's not actually a very good reflection of how much it's going to cost to run the bill's new programs over a decade-long period.
I've given up on expecting honesty from the right . . . but a little more honesty from the left would be nice.