In the face of ugly numbers in a non-partisan Sienna poll and unsettling cracks in his Democratic Party base, Julian Schreibman is going on the attack as he seeks to portray incumbent Congressman Chris Gibson as a Medicaid-gutting, anti-abortion radical Republican. It’s a message the onetime Federal Prosecutor and Ulster County Democratic Committee Chairman hopes will resonate in a newly drawn congressional district that includes large swaths of voters who, for the past two decades have been represented by Liberal Lion Maurice Hinchey.