The Pentagon is reconsidering its arsenal in light of the intense firefight over Ukraine. Would the United States have enough ammunition to fight if a major war broke out today?

Pentagon strategists are faced with this dilemma as they prepare Ukraine for a war with Russia that could last for years as well as as they prepare for a potential conflict with China.

Russia is firing up to 20,000 rounds per day, ranging from truck-sized cruise missiles to bullets for automatic rifles. Ukraine is responding with up to 7,000 rounds per day, including thousands of small-arms rounds, 155 mm howitzer rounds, Stinger anti-aircraft missiles, and now NASAMS air defense munitions.

A large portion of Ukraine’s firepower is provided by U.S. government-funded weapons that are delivered to the front lines almost weekly. The Biden administration made an additional aid announcement on Wednesday, promising to send 20 million more rounds of small arms ammunition to Kiev.

A major land war cannot be supplied by U.S. defense production lines, and some of them, like those for the Stinger, have already been shut down.

Officials are now questioning whether the United States has sufficient weapons stockpiles, and this is putting pressure on its reserves. Would the United States be equipped to intervene in a major conflict today, such as if China invaded Taiwan?

The Army employs many of the same weapons that have been crucial in Ukraine, such as HIMARS, Stinger missiles, and 155 mm howitzer rounds, and is currently reviewing its stockpile requirements, according to Doug Bush, the Army’s assistant secretary for acquisition.

The military aid that the United States provides is either used to replenish stockpiles of supplies or to pay for contracts with businesses to increase production. Over 8,500 Javelin anti-tank systems, 1,600 Stinger anti-aircraft systems, 924,000 artillery rounds for 155mm howitzers, and hundreds of vehicles and drones are among the military aid totaling at least $19 billion that has been committed so far. It’s also provided advanced air defense systems and 38 HIMARS, although the Pentagon does not disclose how many rounds of ammunition it sends with the rocket systems.

In the post-election legislative session, the administration requested $37 billion more in military and humanitarian aid for Ukraine, and asked Congress to approve it before Republicans take control of the House in January. Californian Kevin McCarthy, the leader of the House Republicans and candidate for speaker, has warned that Republicans will not support writing a “blank check” for Ukraine.

Stockpiles cannot be quickly replenished, not even with new money. The production lines for a number of the systems that are proving to be most important in Ukraine were shut down years ago. It costs money to keep a production line running, and the Army had other priorities in terms of spending.

In May, the Pentagon awarded Raytheon a $624 million contract for 1,300 new Stinger missiles; however, the company stated that due to part shortages, it won’t be able to increase production until next year.

According to senior adviser Mark Cancian of the Center for Strategic and International Studies, who examined previous Army budget documents, the 1,600 Stinger systems the United States has given to Ukraine account for roughly one-fourth of its entire arsenal.

According to LaPlante, the HIMARS system, which Ukraine has used so successfully in its counteroffensive, faces some of the same difficulties.

The Army stopped producing HIMARS between 2014 and 2018, according to LaPlante. The Army is now trying to ramp up production to build up to eight a month, or 96 a year, Bush said.

The effectiveness of HIMARS in Ukraine has raised interest elsewhere as well. Poland, Lithuania, and Taiwan have placed orders, despite efforts by the US to send more quickly to Ukraine. It’s possible that U.S. troops won’t have access to the rounds for live-fire training if the conflict continues and more HIMARS ammunition is prioritized for Ukraine.

In order to give Ukraine another shorter-range option against the Iranian drones being used by Russian forces, the U.S. recently announced it would be supplying Ukraine with four Avenger air defense systems, portable launchers that can be mounted on tracked or wheeled vehicles. However, Stinger missiles are also used by the Avenger systems.

Stockpile issues were taken into consideration, according to Sabrina Singh, the Pentagon’s deputy press secretary.