As the Republican Party’s blockade of aid to Ukraine drags into its fourth month, the U.S. government under Pres. Joe Biden has found a clever new way to give Ukraine’s forces the weapons and ammunition they need to defend their country.

It is, in essence, an American version of Germany’s circular weapons trade—the so-called Ringtausch. The United States is gifting older surplus weapons to Greece with the understanding that Greece donates to Ukraine some of its own surplus weapons.

Greek media broke the news last week. According to the newspaper Kathimerini and other media, the Biden administration offered the Greek government three 87-foot Protector-class patrol boats, two Lockheed Martin C-130H airlifters, 10 Allison T56 turboprop engines for Lockheed P-3 patrol planes plus 60 M-2 Bradley fighting vehicles and a consignment of transport trucks.

All this hardware is U.S. military surplus—and is available to Greece, free of charge, under a U.S. legal authority called “excess defense articles.” Federal law allows an American president to declare military systems surplus to need, assign them a value—potentially zero dollars—and give them away on the condition that the recipient transport them.