The Texas Military Department (TMD) is an executive branch agency of the Texas government. Along with the Texas Department of Public Safety, it is charged with providing the security of Texas, which has the second largest population, border, and economy in the United States. It also provides administration of the Texas Military Forces (TXMF), the principle instrument through which it executes security policy. TXMF currently include the Texas Army National Guard, Texas Air National Guard, and Texas State Guard. It formerly included the Texas Rangers, Texas Army, Texas Navy, and Texas Marines.