Ever since Russia’s military annexation of Crimea in 2014, the United States military has increased its presence and overall readiness throughout Eastern Europe. However, despite the presence of some 17,000 American troops on the continent, defense officials have repeatedly called for additional support, pointing out that NATO forces throughout the region are too sparse to actually prevent a Russian invasion if ever one were to occur.

It’s with that concern in mind that the U.S. Army recently announced plans to launch the largest U.S. military exercise in Europe in over two decades, set to commence in the Spring of next year. This new drill, dubbed Defender-Europe 20, will see the deployment of 20,000 additional U.S. troops, equipment, and gear to the European theater where they will bolster the 17,000 already present and be joined by military forces from a number of allied nations for a series of drills and war games.

In a very real sense, this deployment can be seen as two massive logistical and strategic litmus tests for the U.S. military. First, the Army has to demonstrate its ability to rapidly move twenty thousand troops along with their equipment thousands of miles over open ocean. While this type of exercise was done in far larger scale throughout the Cold War, with some such drills including over 125,000 troops, it’s been decades since the Army has attempted anything of the sort. This sort of enterprise is about far more than getting the boots on the ground — it’s about getting vehicles, maintenance, supplies, and support gear on station as well.