My understanding is that Laffer did not specifically approve Cain’s 9-9-9 Plan. He only confirmed that an income tax rate reduction will result in more government revenue (i.e. taxable income elasticity) as illustrated in the famous Laffer Curve.
Per wiki:
“Laffer presented the curve as a pedagogical device to show that, in some circumstances, a reduction in tax rates will actually increase government revenue and not need to be offset by decreased government spending or increased borrowing. For a reduction in tax rates to increase revenue, the current tax rate would need to be higher than the revenue maximizing rate. In 2007, Laffer said that the curve should not be the sole basis for raising or lowering taxes.”
http://en.wikipedia.org/wiki/Laffer_curve
Nope. He approves.
Reagan Economist Art Laffer: Cain‘s ’999‘ is a ’Wonderful Plan’
http://www.theblaze.com/stories/reagan-economist-art-laffer-cains-999-is-a-wonderful-plan/