Earlier this week, while news of the AIG bonuses was still burning into the national consciousness, I linked to Aaron Zelinsky’s suggestion that Tim Geithner should press the IRS to find the payouts nondeductible because they fail to qualify as “reasonable” compensation.

It might have been a more elegant and prudent way of defusing the AIG furore, compared with what we’ll likely end up with. In its haste to been seen as doing something, the House yesterday passed a bill imposing a 90 percent tax on bonuses paid to any employee whose family income is more than $250,000 and who works for a company that has received $5 billion or more in TARP funds. The Senate will likely weigh in with its own bill next week.

Does this tax-it-off-them approach not seem just a tad imperial? Here we have a piece of punitive legislation designed to bring the full majesty of the tax code down on the head of one particular group of people. Can this be even close to constitutional?

Turns out it can, according to Harvard law professor Laurence Tribe. In a note to the Atlantic, he discusses attainder — a legal concept you may not have come across since the last time you were reading 15th-century British history, but which you may remember from Article 1, Section 9 of the Constitution, which states that “no bill of attainder or ex post facto law shall be passed.” The aim, of course, is to prevent the legislature from finding people guilty of a crime and punishing them without benefit of a trial. Only the courts can single out individuals for punishment.

“It would not be terribly difficult to structure a tax, even one that approached 100 percent, levied on some or all of the bonuses already handed out (or to be handed out in the future) by AIG and other recipients of bailout funds so that the tax would survive bill-of-attainder clause challenge,” the professor opines. “The fact that the individuals subject to the tax in its retroactive application would in principle be readily identifiable would not suffice to doom the tax either from a bill-of-attainder perspective or from a due process perspective.”

Bad news for AIG, and for other TARP recipients — many of which, let’s not forget, had the funds practically rammed down their throats by Henry Paulson so that the more seriously troubled firms wouldn’t be stigmatized.

Could be bad news for the rest of us, too, if it opens the door to more scandal-driven, custom-built, confiscatory taxes. ###