The Department of Defense (DOD), established in 1947, provides for the national security of the United States. It consists of the branches of the US Armed Forces: Army, Navy, and Air Force. The Secretary of Defense oversees the military, protects U.S. interests abroad, and maintains domestic order through the National Guard and Reserve forces. The Department of Homeland Security (DHS) , created in 2002 to combat terrorism at home, coordinates federal efforts to prevent terrorists from entering the country or carrying out attacks on American soil; respond to natural disasters; enforce immigration laws; protect the President; enforce drug and firearms laws; protect US borders; assure US computer security against cyber threats posed by nations like China or Russia, who might want to meddle with elections (not all bad stuff!), as well as help states tend to first responders who may be affected by natural disasters or terrorist acts. DHS also manages several agencies that provide emergency services after disasters—including FEMA, which was originally an independent agency under DOD but converted into an agency within DHS when it was created back in 2002.
