The United States has incentives to outsource the production of weapons, as its domestic capacity is insufficient to meet its needs. Co-production benefits others. But it’s also likely to lead to proliferation across borders, create regional security tensions and increase the risk of conflict.

The Trump administration is nearing completion of a new “Buy American” plan that calls for U.S. military attaches and diplomats to help drum up billions of dollars more in business overseas for the U.S. weapons industry, going beyond the limited assistance they currently provide, officials said.