Fitz tries his best to intimidate his veep to get her to pass an important (but poorly written) bill. It doesn't fly. Susan Ross isn't there to advance her own agenda. She's there to help her president make real change. Fitz has no choice but to get on board with changing the bill to make it actually work. They work together, and, as a result, Mellie launches her campaign. Watch this scene from Scandal Season 4, Episode 19: I'm Just a Bill.