It worked great in the 80's. Remember stagflation and the misery gap that Carter left. In comes Ronaldus Magnus and the Laffer curve and voila you have the longest peace time period of economic growth in history. It was only broken by GHWB and his breaking of the no new taxes pledge.
Now before you bring up the deficits under Reagan let me head you off at the pass. First of all he had a very liberal Democratic Congress headed by Tip O'Niel that would not actually cut spending and Reagan aquiessed in his second term. Also Reagan recognized that the USSR could not compete with us economically and he won the Cold War by bankruting the Soviets. We out spent them into the dustbin of history. Defict spending was a small price to pay for the world wide peace it bought.

As for the last 8 years, Bush's tax cuts were wildly successful. He inherited a recession then had 9/11. His tax cuts kept the economy going and up unitll last year we had the highest growth and lowest unemployment ever. Bush however was less able or willing to hold the line on spending and thus our rising debt. The GOP Congress that was booted in 2006 and yesterday's election are reflections of Conservatives disgust with the Republican party and their move away from proven conservative economic principles.

Cut marginal tax rates and you get economic growth. It's undeniable.