I hope someone in the Pentagon dusts off Re-forger, because there's no armor in western Europe;
The U.S. pulled its last tanks out of Europe in 2013, but then Putin invaded Crimea, so the U.S. started Operation Atlantic Resolve which involves nine month rotations of a U.S. armored brigade to Europe and regular multinational training between U.S. forces and those of NATO countries such as Estonia, Latvia, Lithuania, Romania, etc...the Army has also increased its stocks of pre-positioned equipment in such countries. The stocks include Humvees, M1 Abrams tanks, and all sorts of other equipment so that troops can be sent over from the U.S. and be ready to fight without waiting for equipment to be shipped over from the United States.
It used to be that a lot of the equipment was older and less maintained, more there for an emergency, but in recent years, the Army has upgraded much of it to being brand new equipment and said equipment gets regularly used in the Atlantic Resolve operations, so that if crap hits the fan, the troops sent over are utilizing equipment that they are already familiar with. The Atlantic Resolve training also exercises the Army's abilities in terms of interoperability with the NATO countries.
There's actually been quite a bit of debate on this whole issue, for example some say the nine-month rotations are adequate for deterrence and also exercise the military's ability at deploying forces whereas others say that while true, it exercises such skills too much and at the detriment of combat skills, and thus that we need a permanent armored force in Europe. This then leads to disagreements over armored brigade or full armored division. At the Army's current size and global responsibilities, I don't believe it has the resources to place a full armored division permanently in Europe right now.
Then there's the debate over where to put it. Some say Poland (also Poland wants one) while others say (well said, things have changed in the past few weeks) that such a move would be too provocative to Russia and also would be too expensive and complex as it would require construction of a whole new base there (or bases). Some say put an armored division in Germany, as it's further away from Russia and there is a whole existing base infrastructure already there. A criticism to this is that it might make the Eastern European states feel like NATO is viewing them as a buffer zone. However a full division in Germany would still make Atlantic Resolve annual training easier.
