New Jersey Democrats have a rare opportunity to rise from the ashes of the Tammy Murphy debacle and emerge stronger after cleaning house. It may be a naïve hope, but as we just learned again, politics is full of surprises. The first step is to kill the infamous “line” that lets the county bosses manipulate the ballot to give their chosen insiders a lopsided advantage in primaries. That’s the key to boss power, because they can choose who wins the nomination, which is decisive in most districts. Then they can tell dependent legislators what bills to support or oppose. “It’s worse now that it’s …