Ken Starr offered Broaddrick immunity to cover her for her previous statement saying that she was not raped by Clinton. That means he was offering her to NOT prosecute for perjury. However, had she rejected his offer, he would have prosecuted her, like he did McDougal. Some choice. "Say what I tell you is true, or you'll go to jail." I bet he didn't know what really happened, either, but he knew what he wanted from her. 
Ken Starr destroyed his own credibility by his relentless abuse of his power. He further destroyed himself recently by mishandling sexual assault claims at Baylor U. Who cares whether he was once a Supreme Court nominee? It is his abusive performance toward women demonstrated through the Clinton witch hunt and Baylor that ruins him. Jim McDougal was willing to say anything to save himself. His word should have no more value than Susan"s. Again, tell Starr whatever he wants to hear or go to jail. 19-years-old is still adult. Some know more than I do.