There's an ontological question here about what, exactly, McConnell considers to be "evidence." But how about the Congressional Budget Office's
estimations? "The new CBO data show that changes in law enacted since January 2001 increased the deficit by $539 billion in 2005. In the absence of such legislation, the nation would have a surplus this year. Tax cuts account for almost half — 48 percent — of this $539 billion in increased costs." How about the Committee for a Responsible Federal Budget? Their
budget calculator shows that the tax cuts will cost $3.28 trillion between 2011 and 2018. How about George W. Bush's CEA chair, Greg Mankiw, who used the term "charlatans and cranks" for people who believed that "broad-based income tax cuts would have such large supply-side effects that the tax cuts would raise tax revenue." He
continued: "I did not find such a claim credible, based on the available evidence. I never have, and I still don't."
There is some stimulative affect from tax cuts. They increase economic activity somewhat, and that means there's somewhat more taxable revenue for the government to pick up. But not much. Not nearly enough to cancel out the cost of a tax cut. It's important to remember that the Laffer Curve is actually a curve. You can no more drop taxes to 1 percent and make up the difference in revenue than you could increases taxes to 100 percent and sustain enough economic activity to fund the government. You'll recall that the last time we saw budget surpluses was under Clinton -- and higher taxes.
