Megan McCardle makes a great point on the limits of the ability to raise taxes!
Taking your tax rate from 5% to 10% decreases your after tax income by 5.26%. But by the time your tax rate is 50%, you’re only keeping half of your income. So increasing the tax rate by 5% decreases your after-tax income by 10%: you used to take home 50 cents out of every dollar, but now you only take home 45 cents.
If you were surprised that Gerard Depardieu decided to leave France rather than pay the new 70% top rate, think of it this way: the rate increase was only 30%, but it was going to cut his income in half. Yes, that would still leave him with more money than you and I live on. But people don’t think this way: if the government came and took half your after-tax income away, that would still leave you with more money than a middle-class family in Bangalore lives on, and you would still be hopping mad, not to mention panicking about how the mortgage was going to get paid. Even if they only took half of your marginal after-tax income away–an extra 50% of every dollar you made over $40,000 say–you would be pretty upset, because you’ve probably already earmarked uses for those dollars.