Puritans did not agree with the Anglican church so the wanted to change it. They could do that in Massachusetts. Church leaders led the local government and everyone in the colony had to pay to support the Puritan church. - www.manythings.org.
I'm pretty sure he only abdicated once. :)
This would be an example of an unlimited government system. An unlimited government system is when a leader of a government has no restraints on what they can do with a government.
The difference lies in interpreting the two sides of the conflict. McPherson saw the war as the war between the evil South and the good North. He was focused on the abolition of slavery and their integration into the society as free people. Horwitz on the other hand saw South not as evil but as a faction which went to war to protect its economic interests.