Operation Atlantic Resolve is the official name of the unofficial operation supporting the war in Ukraine, and is in response to Russia's invasion of the Donbass region. Operation Atlantic Resolve has been funded under the European Deterrence Initiative, and is intended, thus far, to strengthen NATO. The US has military in Eastern Europe, but has not called on Americans to fight to defend Ukraine. "I hereby determine that it is necessary to augment the active Armed Forces of the United States for the effective conduct of Operation Atlantic Resolve in and around the United States European Command’s area of responsibility," President Joe Biden said. As such, he authorized the ordering of any active duty units of the Coast Guard to serve as a unit of the Selected Reserve. The Selected Reserve is the "the most readily available group of Army Reserve Soldiers," according to the US Military.