@KrankyMike - The 'left' economists also have PHDs. The solution to the problem is hardly clearcut. Stop acting like it is.
I don't think anyone disagrees that tax rates have an effect on the economy. But tax cuts aren't always the answer, just as increases aren't always the answer. People with above $250k/yr have enough money that raising their tax rate a couple points will not effect their standard of living. You can make the argument the author did, that billionaires will stop creating jobs here if taxes are raised (despite the fact they didn't create more when taxes were cut), but I believe the problem is more rooted in lack of consumption by the middle/working class because they have no money. AKA insufficient demand.