What were the chances of a US dictatorship forming to deal with the US Civil War?

Answer 1

Very small, I would say. The values of liberty were still strong in most people's minds, especially considering the reason for the Civil War in the first place being over Civil Rights. The chances of a military Dictatorship forming were also slim, due to the fact that the USA only had a small peacetime standing army and most of the army units raised were volunteers, who only signed up to fight the South and reunite the nation. The three branches of government in the USA were specifically designed so as to avoid any type of tyranny from occuring. Finally Abraham Lincoln openly espoused the democratic values of the USA which it was (partially) founded upon. The only way I can see a dictatorship forming is if a few things happen:

1. Abraham Lincoln dies, and the vice-president is unavailable for whatever reason.

2. The North is losing badly in the Civil War and the military feels the need to take command.

This dictatorship might last until the end of Reconstruction in the 1870's before normal civilian government is restored. As for a brutal fascist or Communist dictatorship arising, I don't think that would ever happen. Especially considering the modern 'dictatorship' was invented roughly after the Civil War.