According to a 2012 IGM panel (cf. reference below), most experts believe that a federal income tax cut would lead to a higher GDP in five years, ceteris paribus. Is this effect purely Keynesian, and based on a presumption that the U.S. was still recovering from the recession and that greater fiscal stimulus was called for, or does it truly reflect a belief among the majority of mainstream economists that the U.S. federal tax regime is sitting on the wrong side of the Laffer curve as the title indicates?
Source: http://www.igmchicago.org/igm-economic-experts-panel/poll-results?SurveyID=SV_2irlrss5UC27YXi