Secretary of the Treasury Andrew Mellon, back in 1920, figured out that if the top income brackets are taxed much higher than an overall 25% rate, they'll simply dump their money into tax-free instruments like municipal bonds and what have you, and Podunkville, Missouri will have plenty of money from the bond sale for their new bridge, but Federal tax revenue will drop, and capital investment in new or expanding business will grind to crawl, further reducing revenue.
It's been proven over and over again, by Mellon, Kennedy, Reagan, and Bush, that tax revenue will increase when tax rates are cut, but still the political left thinks that raising taxes on the top earners is the answer to all the nation's woes. You'd almost think they care more about the number before the percentage symbol than the number after the dollar sign.