There's been a lot of publicity recently about Obama's proposal for a tax on banks which received government aid last year.
He'd certainly have the wind at his back given the widespread populist outrage over the huge bonuses on Wall Street this year.
But since the banks which borrowed money have all paid it back, the proposed excise tax reeks of a "windfall profits" tax similar to the one proposed for oil companies back when the price of oil skyrocketed. And you shouldn't penalize a company merely for being successful.
What the government should do is merely ask the banks which benefited from the AIG bailout to pay that money back to the government. They would get more money ($12.9 billion from Goldman alone) than they would from an excise tax. This would be far more defensible (the banks which took on bad counterparty risk with AIG should never have been recompensed for their bets by the taxpayers). It would abolish the essential unfairness of a tax which was levied merely to get more money from successful companies. And it would quell populist anger (if Goldman had to recompense the government for its AIG payout, those humongous bonuses would be cut back to less outrage-inducing proportions).
Whether the government should be in the business of saving banks it considers to big to fail is debatable. But it should definitely not be in the business of making good on the banks' bad bets so that the banks can then hand out record bonuses to their employees.
The government could impose this payback with the caveat that if AIG ever regains its feet, it could then pay back the banks which had to pay for its failure -- after it pays back the government. (This won't be happening anytime soon.)
This would be fair, and that's all the public really wants.