Exxon Mobil Corp. (NYSE: XOM)'s record-setting quarterly profits last week prompted renewed calls for a windfall profits tax against the oil industry. The problem I have with these theory is that people usually do not explain what they mean by a "windfall."

"How does it differ from your everyday, run of the mill profit?" The Wall Street Journal noted in an editorial today. "Is it some absolute number, a matter of return on equity or sales -- or does it merely depend on who earns it?"

Also, is the government going to figure out how much Exxon deserved to earn and what gives the government the right to single out the oil companies for such treatment. Why not subject Google Inc. (NASDAQ: GOOG) or Warren Buffett's Berskshire Hathawy Inc. (NYSE: BRK.A) to a windfall profits tax too? They make lots of money, right?

Well, the reason why we don't penalize companies just because they make a lot of money is because that would be insane. As the Journal notes, it's hard to make the case that Exxon's profitability is excessive. In 2007, its profit margins were 10%, in-line with the industry average. The oil company's margins were worse than firms in the chemicals industry, pharmaceuticals, beverages and tobacco, the paper said.

Exxon Mobil is a pretty easy company to dislike. Its politics are reactionary, particularly on global warming. Its attitude toward alternative energy is skeptical. Wall Street already gave a thumbs down to its latest earnings report which is a far more effective punishment than a windfall profits tax.

Putting the squeeze on the oil industry may feel good, but it won't bring back $2 gas prices. Those days are gone forever.