Trolop's Phineas Finn

Anthony Trol's Phineas Finn is about a legislator who starts to dip his toe into the world of money and the world of finance. The central dilemma, it doesn't really matter what the issue is, is that he is called upon to vote for something that he cannot support. He will lose his position if he does not vote against his party's interests. There's a sequel called Phineas Redux, which is essentially a potboiler murder mystery also very enjoyable.