By the fall of 1989, the Noriega regime was barely clinging to power. Tensions increased when election results were voided and opposition leaders were physically beaten by Noriega's Dignity Battalions (DIGBATs). An unsuccessful PDF coup attempt in October produced bloody reprisals. Deserted by all but a small number of cronies, and distrustful of a shaken and demoralized PDF, Noriega began increasingly to rely on irregular paramilitary units called Dignity Battalions. In December 1989, the regime's paranoia made daily existence unsafe for U.S. forces and other U.S. citizens.
Planning for the Panama contingency began in February 1988, including a series of orders that addressed the defense of the Old Canal Zone, noncombatant evacuation, neutralization of the Panamanian Defense Forces (PDF), and Civil Military Operations (CMO). The operation plan (PLAN) for offensive operations became PLAN BLUE SPOON. In Sep 89, JTFSO revised PLAN BLUE SPOON. It was changed from BLUE SPOON to PLAN 90-2. The October coup attempt caused PLAN 90-2 to be updated as the PDF displayed the capability to quickly reinforce units in Panama City.
On 15 December 1989, the National Assembly of Panama declared that a state of war existed with the U.S. and adopted measures to confront foreign aggression. In the days that followed, service members and dependents were harassed, and a Marine lieutenant was killed.
On 17 December 1989 the national command authority (NCA) directed the Joint Chiefs of Staff (JCS) to execute PLAN 90-2. JTFSO received the JCS execute order on 18 Dec with a D-Day and H-Hour of 20 Dec 0100 local. The operation was conducted as a campaign with limited military objectives. JTFSO objectives in PLAN 90-2 were to:
A. Protect U.S. lives and key sites and facilities.
B. Capture and deliver Noriega to competent authority.
C. Neutralize PDF forces.
D. Neutralize PDF command and control.
E. Support establishment of a U.S.-recognized government in Panama.
F. Restructure the PDF.
At Forts Bragg, Benning, and Stewart, D-Day forces were alerted, marshaled, and launched on a fleet of 148 aircraft. Units from the 75th Ranger Regiment and 82d Airborne Division conducted airborne assaults to strike key objectives at Rio Hato, and Torrijos/Tocumen airports.
On December 20, 1989, the 82d Airborne Division conducted their first combat jump since World War II onto Torrijos International Airport, Panama. The 1st Brigade task force made up of the 1st and 2nd Battalions, 504th Parachute Infantry Regiment, parachuted into combat for the first time since World War II. In Panama, the paratroopers were joined on the ground by 3rd Battalion, 504th Parachute Infantry Regiment which was already in Panama. After the night combat jump and seizure of the airport, the 82nd conducted follow-on combat air assault missions in Panama City and the surrounding areas.
They were followed later by the 2d and 1st Bdes, 7th Inf Div (L), while the in-place forces comprised of the 3d Bde (-), 7th Inf Div (L); 193d Infantry Brigade (L) and 4-6 Inf, 5th Inf Div (M), assaulted objectives in both Panama City and on the Atlantic side of the Canal. By the first day, all D-Day objectives were secured. As initial forces moved to new objectives, follow-on forces from 7th Inf Div (L) moved into the western areas of Panama and into Panama City.
Urban terrain provides high potential for fratricide because of the likelihood of close quarters (high weapons density), recognition problems, and unfamiliar secondary effects of weapons. During Operation JUST CAUSE soldiers employed several ineffective and dangerous techniques to breach various fences, walls, and barred doors with grenades, rifle fire, and even anti-tank weapons. Direct fire support, even from just a block away, is very difficult to control. During JUST CAUSE mechanized forces providing fire support were told by brigade a light force had cleared a tall hotel building only to the second floor. In actual fact, it had cleared to the tenth floor and was fighting in a counter-sniper engagement. Seeing this fire and apparently some weapons protruding, the mechanized forces began to suppress. This drew return fire from the friendly light force for some seconds before coming under control.
The US troops involved in Operation Just Cause achieved their primary objectives quickly, and troop withdrawal began on December 27. Noriega eventually surrendered to US authorities voluntarily. He is now serving a 40-year sentence in Florida for drug trafficking.
Operation JUST CAUSE was unique in the history of U.S. warfare for many reasons. As the largest single contingency operation since World War II, it focused on a combination of rapid deployment of critical combat power and precise utilization of forward deployed and in-country forces.