 Complete the following phrase:  Upon graduating from West Point, Lyon was commissioned as a 2nd lieutet and assigned to the 2nd U.S. Infantry Regiment after graduation and served with them in the Seminole Wars and the MexicanAmerican War. Despite denouncing American involvement in the Mexican War, he was promoted to first lieutet for conspicuous bravery in capturing enemy artillery at the Battle for Mexico City and received a brevet promotion to captain for the battles of 