The President is both the head of state and head of government of the United States of America, and Commander-in-Chief of the armed forces. Under Article II of the Constitution, the President is responsible for the execution and enforcement of the laws created by Congress.
You can join some branches of the United States military at the age of 38 years but not others. The Army, Navy, Air Force, Marine Corps and Coast Guard each has its own minimum and maximum age requirements for enlistees, including for new recruits in the active-duty ranks, the Reserves and the National Guard.
The Army is also the largest branch of the military. Along with active duty soldiers, the Army also has two reserve components-the Army Reserves and the Army National Guard.he Marines are the second smallest branch of the military. Their purpose has changed somewhat over the years. When it was first established in 1775, it was under the Navy as a ground force element of the branch.