Why supply side arguements persist?

James Surowiecki writes about why the "snake oil remedy", as Paul Samuelson castigated it, still dominates the right wing opinion on taxation. The argument that "tax cuts pays for itself" has become one of the sacred truths of the Republican and right wing establishment. Calling it the "great lie of the supply side economics" in Tax Evasion, he argues tht it is a smokescreen for cutting taxes for the rich. The article contains a few links to the supply side position and the studies that conclusively debunks it.