It basically suggests that: a)top tax rates have historically had virtually no significant effects on overall economic growth
b)we are well below the optimal tax rate for maximizing revenues
The authors of the paper on which this summary article is based on go on to suggest an optimal top effective rate of 68.7% as the revenue maximizing point (basically the optimal trade-off between revenue and dampening effects and/or evasion)
I find this work pretty convincing...
Further, I don't really see how a high top income tax bracket would affect much. It doesn't look to me like it affects businesses (its not a corporate tax) - only the pay of people at the top of the chain. Are those people going to revoke their citizenship and move elsewhere to avoid the taxes?
The higher the tax rates go, the more fortune 500's will move their cash to places where it is not being taxed as heavily.