Because it was a threat to American citizens. It was close enough to do major harm.
Freedom of speech :) (and religion and press) i needed more letters lol
Transporting goods over long distances", since this was far easier and cheaper than transporting goods over land.
It is debated. He announced the Emancipation Proclamation on his own to weaken the Southern States, but later on needed approval for the passing of the 13th amendment