Soldiers from the 2nd Brigade Combat Team, 4th Infantry Division of Fort Carson, Colo., unpack Stryker combat vehicles on April 10, 2025, after they were recently shipped to Fort Bliss, Texas, for use in detecting illegal activity at the U.S. border with Mexico. (Rose L. Thayer/Stars and Stripes)

WASHINGTON — The U.S. military relies on a network of countries around the world to produce the sophisticated weapons and equipment that arm its warfighters.

It imports missiles from Norway and specialized technology from France and Italy for fighter jets. It equips Army soldiers with a recoilless rifle produced by a Swedish company and depends on Canada to assemble combat vehicles such as the Stryker.

“There’s not a single weapon system that I know of that doesn’t have some type of foreign content,” said Bill Greenwalt, a former Defense Department acquisition official now at the conservative American Enterprise Institute, a Washington think tank.

That global supply chain, built up for decades, could now be under threat as President Donald Trump’s administration seeks to lessen American reliance on imports and bring more manufacturing back to the United States.

Tariffs imposed in recent weeks on nearly all foreign-made products and the prospect of more levies to come could make American weapons more expensive, dampen weapon sales abroad and tarnish the reputation of the U.S. as a reliable partner, according to some experts and lawmakers.

“In the short term, the announced tariffs alone will increase costs for U.S. defense industrial supply chain companies,” Sen. Jeanne Shaheen, D-N.H., wrote in a letter last week to Defense Secretary Pete Hegseth. “In the long term, tariffs will drive up the Department of Defense’s contracting and procurement costs, limit the Department of Defense’s buying power and ultimately harm the warfighter and our military readiness.”

In addition to 25% tariffs on steel and aluminum, the Trump administration has implemented a blanket 10% tariff on most U.S. trading partners. A plan to introduce higher tariffs on nearly 60 countries has been paused until July while a trade war with China has raised tariffs on Chinese imports to 145%.

A Pentagon official said Friday that the department is “closely monitoring existing tariffs and their impacts on procurement and manufacturing of goods overseas with international partners and allies.”

The Defense Department has agreements with 28 partner countries that allow it to override congressionally mandated “Buy American” requirements and engage in billions of dollars of defense trade with countries such as the United Kingdom, Germany and Japan, according to the Government Accountability Office, a federal watchdog.

It is unclear how those arrangements will be affected by Trump’s tariffs and whether the defense industry will be strategically carved out of the levies, as business groups and some lawmakers have been requesting.

“Right now, you just have to operate on the fact that prices are going to go up because there is foreign content,” Greenwalt said. “A lot of this foreign content is because of agreements like we have with the F-35 [fighter jet] but the majority of it is because our allies produce better technology than we do.”

Dak Hardwick, vice president of international affairs at the Aerospace Industries Association, said the trade group has received an assurance from the Trump administration that duty-free entry for materials destined for the military would continue.

The nearly 300 aerospace and defense companies who are members of the association continue to seek clarity from the administration and are engaging with their foreign counterparts, Hardwick said.

“Sales to international partners are critical for the health of the U.S. defense industrial base,” he said. “We want to continue to do those sales because it keeps our industrial base lines humming, it certainly keeps them warm at times when the U.S. government isn’t necessarily buying certain types of capabilities.”

While the U.S. received 3.1% of global arms imports from 2020 to 2024, it leads global trade in weapons with a share of 43% of exports, according to the Stockholm International Peace Research Institute.

Tariffs could chip into that dominance by raising the cost of U.S. defense products domestically and abroad.

“You’re going to see a greater instance of ‘Buy Europe’ and ‘Buy Asia’ and that’s going to lead to fewer aerospace and defense sales for the United States and drive down the one place that we have a large positive trade balance,” Greenwalt said.

The Philippine ambassador to the U.S., Jose Manuel Romualdez, told Reuters earlier this month that tariffs could affect his country’s economy and its ability to pay for a potential $5.58 billion purchase of F-16 aircraft from the American defense manufacturer Lockheed Martin.

“These F-16s ... are very expensive for us ... and we won’t be able to afford it if, obviously, we won’t have the resources to be able to buy them,” he said.

Other countries are scrutinizing their security dependence on the U.S., seeing the Trump administration’s “reciprocal” tariffs as evidence that the U.S. is becoming an erratic supplier and customer, according to Greenwalt.

Some lawmakers in recent weeks expressed particular concern about the defense relationship with Australia, which has an agreement with the U.S. and the United Kingdom to acquire nuclear submarines. Australia had free trade with the U.S. before becoming subject to the Trump administration’s 10% “baseline” tariff.

Australian Prime Minister Anthony Albanese said the levy was “not the act of a friend” and some within his center-left Labor Party have questioned whether the U.S. can be relied upon to deliver the submarines.

“There is definitely collateral damage to our allies,” Rep. Joe Courtney, D-Conn., said of the tariffs at a congressional hearing earlier this month, noting he has been in touch with Australian parliament members.

In Canada, Prime Minister Mark Carney declared “the old relationship we had with the United States, based on deepening integration of our economies and tight security and military cooperation, is over.”

American defense companies are bracing for retaliatory measures — it’s something that’s “top of mind,” Hardwick said.

The European Union, which recently launched a rearmament effort focused on purchasing weapons from European manufacturers, prepared to hit back with counter-tariffs of nearly €21 billion before Trump paused his 20% tariffs on the bloc.

China has responded to Trump’s moves with a 125% tariff on U.S. goods and most pointedly, a limit on exports of certain rare earth minerals and magnets essential for defense technology such as missiles, radar systems, drones, robotics and jet engines.

Trump issued an executive order last week directing Howard Lutnick, the commerce secretary, to open a national security investigation into potential new tariffs on all U.S. critical minerals imports, escalating the fight.

The consequences for the military industrial base could be steep. A single F-35 contains 900 pounds of rare earths, a Virginia-class submarine contains 9,200 pounds of them and China processes 90% of the world’s rare earths supply.

“Even before the latest restrictions, the U.S. defense industrial base struggled with limited capacity and lacked the ability to scale up production to meet defense technology demands,” according to an analysis by the Center for Strategic and International Studies think tank. “Further bans on critical minerals inputs will only widen the gap, enabling China to strengthen its military capabilities more quickly than the United States.”

There were signs this week that the trade war could be abating somewhat. Trump on Wednesday said the 145% tariff that he put on Chinese imports will “come down substantially.” Treasury Secretary Scott Bessent said he was engaged in trade negotiations with more than a dozen countries.

Defense companies have, for the most part, expressed optimism that they will be able to weather the changing tariff policies with minimal impact on business, with Northrop Grumman saying Tuesday that it did not yet see significant risk to its programs.

But defense contractor RTX, formerly known as Raytheon Technologies, cautioned it could take a $850 million hit in profit if global tariffs and separate levies on steel and aluminum and goods from China, Canada and Mexico remain in effect through the year.

“Like many companies in the industry, our supply chain and customer base are global, and we import raw materials, parts and modules from around the world,” CEO Chris Calio said in an earnings call. “In light of this, we would be impacted if the current environment were to stay in place.”