“Frustration with the investigation stews inside him until it bubbles up in the form of rants to aides about unfair cable television commentary or as slights aimed at Attorney General Jeff Sessions and his deputy, Rod J. Rosenstein. And, of course, it emerges in fiery tweets about the ‘WITCH HUNT’ — or, as he wrote Thursday morning, shortly before an event promoting leadership in technology, ‘a big Dem HOAX!'” More …