The effort to bring casino gambling to Massachusetts is “on the verge of being a mess,” according to a gaming policy expert. Voters in Palmer and East Boston rejected casino projects on Election Day. There is the possibility some casino developers won’t pass a strict background check. WAMC’s Pioneer Valley Bureau Chief Paul Tuthill spoke with Clyde Barrow, a professor of public policy at UMass Dartmouth, who specializes in the gaming industry. He asked Barrow to assess the current state of casino development in Massachusetts