A work of fiction, but loosely based on the political career of Huey Long. Wikipedia talks about some of the themes in the book but for me the central question was the thread of if you can do good and make good works from bad means (or, "do the ends justify the means")?

The ultimate answer to this in the book is "not directly" -- Willie Stark fails in his primary goal of a hospital for all, but Jack Burden manages some level of "happily ever after" though not deliberately and more as an unlooked-for byproduct of pursuing a good goal through evil means.