Geoffrey, how is taxing an oil company protecting the well-being of the whole commonwealth?
First, I dealt, in general, with the legitimacy of the taxation power of the state in an earlier comment on this same post.
From a Constitutional standpoint, Congress has the freedom to regulate interstate commerce (it even has a name, the commerce clause). Second, from a theoretical standpoint, it is important to remember that businesses exist because of government; markets exist because of government. Without the monopoly on police power enjoyed by the state, there would not be enough order to control forces that would destroy any economic regime. Furthermore, since corporations are entirely a product of the state, I see no reason in the world why the state should not regulate them in some manner.
Furthermore, in order for the state to continue to exist to provide a safe area in which economic activity can thrive, taxation is necessary to fund the continued police power of the state. This is an elementary bit of political theory. It is also common sense. If corporations want to operate without rules, they need to understand that not only will there be no regulation or taxation, there will also be no protection from criminal activity directed against them, or unethical, immoral or other actions detrimental to their continued survival in such a non-state as well.
I think this answers Cameron's question in general, should he care to read it again. If not, I shall elaborate.
States have been exercising taxation power from time immemorial. From a practical standpoint, the power to tax needs no theoretical justification; it has always been a part of our common life. To pretend otherwise is to ignore history and reality. No one enjoys paying taxes in any form, whether it is income taxes, sales taxes, property taxes, what have you. Virginia has what is colloquially known as a "personal property tax", but is just a "car tax"; it is so loathed that one governor, Jim Gilmore, road to victory in 1997 by promising to rebate all of the previous year's personal property tax payments. This kind of feaux-populist garbage may win votes and influence various pin-headed "thinkers", but it hardly constitutes good government or good policy making.
Corporations have been deemed, by Supreme Court ruling, persons under the law. As such, they are not just subject to (somewhat limited) freedoms and rights (including limited free speech rights and protection from illegal takings under certain conditions), but are also subject to certain obligations with which persons must comply, under the law. One of those obligations is to contribute monies to the state for its continued existence.
Unlike ideologues of all kinds, whether they be socialists, free-marketeers, libertarians, or dyed-in-the-wool syndicalists, the fact is that, in the United States, our laws define what is and is not "proper". Congress, the people's representatives, enacts laws, which are in turn signed by the President. Provided these laws do not abrogate the Constitution that sets the limits on state action, these laws define what is in the best interest of the entire country. If Congress decides that a windfall profits tax should be levied on Big Oil, by definition that makes it in the interest of the entire commonwealth.
I believe we are a non-ideological society. We are a constitutional republic; as such, we are defined not by some theory of government, whether based in economics, race, culture, or what have you. Unlike Britain, whose constitution is unwritten, who we are is set down in a piece of paper hammered out in compromise, first, by a bunch of gentlemen farmers, lawyers, publicists, and businessmen back in 1787, and then amended on occasion in the ensuing 220-plus years to reflect changing attitudes (mostly a growing democratic and egalitarian spirit). This document is all the theory we Americans need to really understand what the state is and how and why it acts.
I think it only fair to repeat - the state has always enjoyed the right to tax those who enjoy its protection. Requiring those who live under the umbrella of its protection to contribute to that protection is a fundamental duty of the state. We can quibble over what constitutes a proper level of taxation, or whether a particular group or another is contributing its fair share; that is the work of legislatures. At its most basic level, however, the fact remains that taxation of any kind is part and parcel of living as a social animal.