This article from the New York Times states the case for adding a public option to Obamacare as well as anything else I've ever read. It forces us to face the fact that the private sector doesn't have the resources--or, for that matter, the will--to provide coverage for everything through market forces alone. It accepts and outlines the need for the government to create competition in order to bring more people into the marketplace and help to drive costs down. It points out that conservatives in the previous Administration under George W. Bush effectively did exactly that, by adding the prescription-drug benefit to Medicare. And finally, it notes that Medicare is already a single-payer system that is highly popular and government-sponsored. Why not effectively make it the public option by allowing people to buy into it? Among other things, it would help to ensure the fiscal solvency of Medicare.
The only thing I would want to add are a few observations about the role of government in the marketplace generally.
Conservatives like to pretend that there should be no such thing. But the harsh reality is that, even to do the very limited things that they think government should do (e.g., public health, the criminal justice system and national security) requires the government to go into the marketplace and compete with private interests for resources, natural and human. By definition, this activity has an economic impact all by itself. I've often thought that the solution to poverty should be giving Defense Department jobs to the poor. They'd be working, and conservatives would fight like hell on their behalf.
It is time--it is, in fact, long overdue--for the United States to stop being the only developed country in the world that doesn't guarantee health care as a basic right. If conservatives looked at the health care systems in the countries that we compare ourselves too, they would discover that those systems pass a basic conservative test: they work. It's high time ours did as well.
So let the government create health care competition. And, in the process, guarantee health care for all.