Over at Left in the West, Matt Singer lays out the crux of the argument, both practical and political, for the public health insurance option as envisioned by President Obama, Senator Max Baucus, and Health Care for America Now:

In Mike Dennison's writeup this morning, he notes, correctly, that the Massachusetts plan that is similar to Max's plan has not controlled costs as much as it wanted to — with attendant concerns for individuals, business owners, and taxpayers.

But there's a meaningful difference between Max Baucus's plan and the Massachusetts plan: Max Baucus's plan contains a public health insurance option. There should, of course, be a difference between the plans. Mitt Romney was Governor of Massachusetts when the plan passed. Barack Obama, who also supports a public health insurance option, is President of the United States.

Why is a public health insurance option so crucial? Bottom-line: it gives consumers an option besides the private insurance sector and, as such, keeps private insurance honest.

Jacob Hacker, a wickedly smart individual and fierce advocate of a public health insurance option, explains the need for a public health insurance option vis a vis constraining health care costs.

Basically, though, we need to get past what I'll call the Massachusetts plan (only private insurance) and the single-payer plan (only public insurance) and look at hybrids that combine the choice and competition of Massachusetts with the accountability and cost-containment of single-payer.

A hybrid system, with a choice of both public and private health insurance options, is in some ways a centrist position. It is not a radical change, it preserves choice, and it also can solve the problems inherent in our current health care system, like affordability, equal access, and poor outcomes. And, as Jocob Hacker posits, it might even be superior to the public only (single-payer) or private only (Massachusetts plan) systems.

Now, the public health insurance option also has the largest possibility to eat into private insurance profits, and so it's going to be the piece of Obama's plan that's most opposed by business and their aligned conservative groups. Of course, they current system is so bad, it almost seems like insurance companies are getting off on our pain:

We're out to change that system and make them play fair. As Chairman Henry Waxman says, the public health insurance option will produce "creative tension" that will make both systems more honest and cost less. It'll be a long fight, but it's a fight we can win.