Here’s the study:
http://graphics8.nytimes.com/news/business/0915taxesandeconomy.pdf
(it was the Congressional Research Service not the CBO so sorry for misstating that it was put out by the CBO)
If you read through and look at the statistical analysis there is no statistically significant link between marginal tax rates and GDP. If anything GDP growth has been slowing since we started lowering marginal tax rates but again it’s not statistically significant.
But there is a significant link between marginal rates and the concentration of wealth at the top.
What needs to be argued is if concentration of wealth is harmful to the economy or not.
I think in some ways it can be harmful, but sometimes that's only half the story. I do not approve of the way the TARP was pushed through. At that time I predicted that even if it was needed to save the economy, (and even Obama agreed that it was, although I still have doubts), it would start a very unfortunate trend of various entities asking for bailouts. That trend seems to be a tradition now. It started with wealthy, government-connected entities asking for help.
That is not to say that concentration of wealth is inherently harmful.