What the author has overlooked is that taxes lower the effective return on all investments. If capital gains generating investment X is better than capital gains generating investment Y when capital gains is taxed at 15%, X will still be better than Y if capital gains is raise to 20% or even to the 39.9% it was in 1976, and so in choosing between X and Y, the rational investor will still choose X.This certainly might be a true statement, or not, depending on the specific tax policy. Can you tell me exactly what policy Buffett was advocating? Because I couldn't find it.
There are 3 possible arguments here.
Argument 1: I, being rich, should pay more money. I don't think Buffett is saying that, because if he felt that way he would just pay more.
Argument 2: The government needs money. We have it. They should come and take it. I couldn't find any mention of government need. He's not saying that the super rich should pay more because it's needed. He's saying they should pay because it's the right thing to do.
Argument 3: The rules should change so that things are "fairer". If this is his argument, which I think it is, then what, exactly does he want to change? Without knowing that, you can't make heads or tails of whether or not tax policy would effect everybody the same or not. Note that if he's arguing for specific policy, it might be that he personally ends up paying no more, or even less. If this is his thesis, then how much he or his buddies actually end up paying has nothing to do with it. He should describe what exactly would be "fair".
There's no argument here, really. It's just Buffett saying he should pay more of his fair share and some friendly poking at the Republicans. His piece seeks to convey feeling, not make a case and support it (Note the folksy telling of how much experience he has and how rates don't matter.) That't great -- it could still be an awesome article. But it doesn't hold together well to try to take the ideas and go somewhere with them.