The so-called "Buffett-Rule," which would impose a minimum tax on incomes above $ 1 million, would guarantee lower tax revenues for the US Treasury. Folks with high income would simply choose to lower their taxable income. That is a fairly simple thing to do and always happens when you raise tax rates on wealthy citizens. Short of confiscating folk's wealth, something Obama may get around to eventually, raising tax rates just encourages tax lawyers and leverage (the wealthy borrow more to live and let their assets grow unrealized...that solves the problem of lowering your taxable income without affecting your lifestyle).
Meanwhile, as tax revenues collapse, the Obama folks will find a way to tack on a tax increase for the middle class to offset the revenue loss from rich folks. This is always the route that tax rate increase advocates end up taking. The result: the middle class gets soaked with more taxation, while the no-nothings revel in the irrelevant higher rate structure that wealthy folks face, but do not pay. This is the kind of absurdity that Obama's class warfare will lead to. No wonderrich people support higher tax rates. Buffett knows he will pay less under Obama's soak-the-rich tax than he does now, so why worry? (Once the new rates are passed, Buffett will lob a call into his high priced tax attorney and get the advice he needs to pay less taxes under the Obama plan than he pays now. Don't think he won't make that call. He will).
Meanwhile, higher marginal rates will mean that money that would have flowed into the capital markets to create new businesses and new jobs will lie dormant in frozen assets. High levels of unemployment, economic stagnation and increasing misery for the poor, minorities and old folks will be the Obama legacy. This is what happens when economic policy is an outgrowth of coffee-house conversations at Harvard by people who have never held a real job.