Why did Salmon Chase go from a Radical Republican in 1860-4 to a Democrat who contested that party's nomination in 1868? He apparently said it was because of Republican overreach on civil liberties restrictions in the south, even though he supported the 14th and 15th Amendments, but that doesn't seem sufficient impetus for someone to switch to a party that he otherwise had little in common with (even supposedly endorsing Vallandingham in the early 1870s). Was it really that simple?