State Sen. Andrew Roraback has scheduled a 2 p.m. news conference in Hartford to criticize what he calls an “unprecedented” effort by a PAC with Democratic ties to attack his candidacy for the 5th Congressional District primary. Patriot Majority USA, with big contributors from AFSCME and the SEIU, recently filed documents with the FEC reporting ad buys targeting Roraback. The TV ad portrays him as a supporter of higher taxes. With the most legislative experience among the four primary candidates, Roraback, if he wins, would give the suvivor of the three-way Democratic primary the toughest race, in theory. The PAC has also gone after Republicans in Nevada and Montana,