The government enforces the rule of law. The rule of law imposes predictability to ones actions and a set of enforceable property rights. I can now sue for breach of contract, even if the guy is Bill Clinton's buddy. I know that if I build a set of retail stores on my land, I will be able to lease them for years to come. All of these things flow from the existence of predictable rights enforceable by the government. In that sense, Will is 100% right.
Think! This was the genius of the founding fathers. They were creating a government. Not a non-government. That government was well designed to release capitalism from the shackles of anarchy and petty tyranny. Of course the government can destroy capitalism also. But the flowering of capitalism in the past 200 years has indeed been a government program.
As for anarchy, wouldn't the free market handle that? If there were truly bad companies wouldn't they everntually fail due to lack of support from either other businesses (suppliers) or customers. Maybe I'm a bit niave on that point.