Please do not copy word for word, you WILL need to rephrase everything I say in your OWN WORDS.
The executive branch and the legislative branch are two complete different things, and both have different jobs. The executive branch enforces the laws, and legislative creates the laws. It's a question to be reckoned with-- Who was going to enforce laws between the north and south? The executive branch. Of course, the legislator is the reason it passed, but they cannot enforce any laws, they cannot hold trials, they only lead it up into the Judicial branch. To put this bluntly, someone needed to enforce it.
I could not be entirely correct, as I'm going based off what I know of the reconstructive plans, and the government branches. If you care to knowledge me more on what the reconstruction plans, I could possibly change it up and put it towards a more accurate response.
