On current trends, we're heading toward a world in which only the human people pay taxes. We're not quite there yet: The federal government still gets a tenth of its revenue from corporate profits taxation. But it used to get a lot more - a third of revenue came from profits taxes in the early 1950s, a quarter or more well into the 1960s. Part of the decline since then reflects a fall in the tax rate, but mainly it reflects ever-more-aggressive corporate tax avoidance - avoidance that politicians have done little to prevent. Which brings us to the tax-avoidance strategy du jour: inversion." This refers to a legal maneuver in which a company declares that its U.S. operations are owned by its foreign subsidiary, not the other way around, and uses this role reversal to shift reported profits out of American jurisdiction to someplace with a lower tax rate. The most important thing to understand about inversion is that it does not in any meaningful sense involve American business "moving overseas." Consider the case of Walgreen, the giant drugstore chain that, according to multiple reports, is on the verge of making itself legally Swiss. If the plan goes through, nothing about the business will change; your local pharmacy won't close and reopen in Zurich. It will be a purely paper transaction - but it will deprive the U.S. government of several billion dollars in revenue that you, the taxpayer, will have to make up one way or another.