The United States now faces an increasing strain on its reserve supply of armaments due to the war in Ukraine. Since the conflict began, the United States has sent over $17.5 billion USD in military aid. These packages have included everything from radar and stinger anti-aircraft rocket launchers to cold weather gear and body armor. As the spending for Ukraine increases, predictions indicate that reserves of certain weapons systems and munitions will soon be depleted to sub-optimal levels required for the United States to effectively respond to a direct conflict. Current supply levels remain adequate for certain armaments; however, this issue will be compounded by the slow adjustment of manufacturing to replenish weapon stocks.
Depleted reserves of munition and military equipment creates two problems in terms of speed: speed in replenishing weapon stocks; and speed of training in the event of a crisis. The process for approving the purchase of military armaments and the subsequent surge in the production can take years, even decades, for certain military equipment. Likewise, a lack of available weapons systems to train troops also lengthens the time necessary to adequately respond to a conflict. Insufficient materials for training indicated prolonged or insufficient troop deployment, both of which are costly on the scale of an international conflict.
The ability of armament manufacturing to respond to rapid changes, or surges, in demand is weak. Manufacturing capacities have not been augmented for use during a conflict and are currently calibrated for peacetime output. Even when comparing production following the United States involvement in World War II, it took years for full production output to be reached. Purchasing patterns have reflected this lack of adjustment as well, with the US only allocating relatively small purchases compared to the rate of depletion for its armaments. Army and Navy munitions suppliers are aware of the shortcomings in the manufacturing process and have asked for budget increases from congress in order to modernize production systems.
Each military branches’ production capabilities are affected by the complexity of its weapons systems and platforms. A report published by the Center for Strategic and International Studies analyzed the surge response rate of each military branch, i.e., Army, Navy, Airforce, and Marines, to determine which would have the longest replenishment time. The findings indicated that the Army, despite being the largest of the branches in terms of personnel, has the fastest replenishment time compared to the Air Force and Navy. The Marine corps has the overall fastest replenishment rate but less than half of the personnel compared to the Army. The report also analyzed the possibility of civilian analogs (substitutes) influencing production capacity and found that the Army had the most substitutes.
The report only indicates complexity as a causal driver for the varying rates in replenishment. For example, the navy takes years to replenish supplies because the time and resources needed to build a ship are exponentially higher than an armored vehicle. The report also found that space-based systems and missiles/munitions had the longest replacement rates, with Navy shipbuilding being an outlier due to the complexity and total costs of production. The Air Force faces also faces huge replenishment times for the same reason.
The aid packages to Ukraine have put more strains on certain armaments than others. It has been reported that the United States has sent 1/3 of its stinger and javelin rocket launcher reserves to Ukraine, and over 1.5 million shells of 155mm howitzer. High Mobility Artillery Rocket Systems (HIMARS) have comprised a critical weapons system for the Ukrainian military and have thus been heavily demanded. The United States has sent several systems, around 16, and is currently seeking to increase production capacity to over 500 by 2028.
To alleviate the strain on supply systems, several groups such as the Naval Surface Warfare Center Indian Head Division, have suggested an immediate increase in production bases and to not wait until a crisis to respond. Because of the critically slow reaction time of manufacturing bases, investments now will alleviate strains on supplies in the future. Leadership in the military and government contractors that lead production of mission critical armaments are aware of these shortcomings.