The foundation of America and the shrugging off colonial (British) rule is one of the greatest flashpoints in world history. The birth of a federal constitutional republic is a revolutionary concept that's more than ripe for the shadowplay and conspiracy that the Creed series is known and loved for. I'm going to fire up the Animus I happen to have in my garage and come up with some possible plot ideas. Cue music.
The year is 1763. After Templar-controlled England nearly bankrupts the British Crown with the Seven Years War. The Templars (namely King George III) see the American Colonies as fertile new ground for exploitation and start bleeding the colonists with unfair taxation. The Redcoats are the footsolders of the Templar's attempting to gain further control of not just the British colonies, but the European continent as a whole. The Templars has already infiltrated various elements of the French aristocracy and the order is poised to make a comeback in a very big way. A whole New World to search for the mysterious Pieces of Eden.
Unfortunately for the Templars, some members of the Assassin's order have already become colonists well before the outbreak of the Revolution. Adding the infiltration of the Freemasons by individuals like Benjamin Franklin (head of the American Assassin's Order) and John Adams, the Order sows the seeds of revolution against the British and their Templar masters.
December 13th 1773: The Assassin's Order launches their first strike against the British and the Templar-controlled East India company on a cool Boston night.