In the 1980s, the United States Army increased light forces to address contingencies and increased threats requiring a more deployable force able to operate in restrictive environments for limited periods. At its height, this included the 6th Infantry Division (light), 7th Infantry Division (light), 10th Mountain Division (light infantry), 25th Infantry Division, and the 75th Ranger Regiment. Operation Just Cause is often cited as proof of concept. Almost 30,000 U.S. Forces, mostly light, deployed to Panama within a 48-hour period to execute combat operations. On 30 September 1985, the 29th Infantry Division (Maryland and Virginia Army National Guard) was reactivated at Fort Belvoir, Virginia as the only light Infantry Division in the US Army's reserve components.