Antonis Samaras’s ambition to drive Greece out of its rescue program is running into a roadblock. The country’s prime minister might be thwarted by conditions for the European Central Bank’s asset-purchase program, as detailed by President Mario Draghi, Bloomberg said. Policy makers meeting in Naples yesterday were resolute that Greece should stay under economic surveillance to be eligible, according to a euro-zone central-bank official involved in the negotiations. Draghi pledged to buy asset-backed securities and covered bonds for at least two years, and said that Greece and Cyprus must be subject to bailout programs to ensure their inclusion because their credit ratings are below investment grade.