Someone above claimed Butler was against corruption. Thats "poppycock"! Butler, though never himself convicted of corruption, wallowed in the accusations. They followed him around for almost all of him career. Much of his money was made in Court defending political allies accused of corruption. Butler was a fan of the spoils system and corruption when his allies were in power, and against it when they were out of power. (Standard attitude for the times).
I like Butler, after reading Hans Louis Trefousse's "Butler: The South called Him Beast!". Roaringly good read. He was certainly a supporter of the underdog and it seems a natural move from supporting the working classes of Massachussetts, and his home Lowell in particular (with a surprising number of women workers even before the Civil War) against the Whig upper classes to support for emancipation against the Southern aristocracy.
Part of his charm as well as his biggest flaw was the outrageously partizan way he approached everything in life. He was a marmite character. But having read this biography the only truely "out there" attitude he had for the times was his support for the Greenback cause which was well before its time had come...