san francisco linkedin cofounder reid hoffman say tuesday republican presidential candidate donald trump would terrify effect domestic foreign policy elect comment come one day hoffman publish article medium.com pledge support crowdpac crowdfunding campaign promise donate veterans cause trump release tax return hoffman say article match five time crowdfunded amount donate million campaign raise 90,000 hoffman tell crowd techcrunch disrupt 2016 san francisco denial possibility trump presidency encourage efforts hold candidate accountable trump campaign immediately respond request comment trump face criticism release tax return political practice require law do every white house nominee since 1973. campaign last week release 10 years return vice presidential nominee mike pence repeat pledge trump would release return government complete audit saw campaign say exactly right way make message message support folks give great service country donald trump concern make america great say care veterans hoffman say linkedin 's hoffman trump presidency would 'terrifying policy