Besides, germany wouldn't really have a chance. The few nuclear rockets we control would probably not be ready in time. The USA could just bomb germany down, like it was planned in case of a war with the UDSSR.
M.A.D. still exists by the way. It's still why all major nations are at peace and why the EU gave so much flak to the US a few years ago when Bush wanted to install a nuclear shield. He later had to back down or serious stuff would've happened. (afaik)
Also, according to wikipedia, Europe has 150 to 240 nuclear warheads. Plenty enough to destroy all US major cities.
But... but... what about childish power fantasies and world conquest?
In all seriousness though, the EU does not currently extend to defense; it is currently only a political and economic union. France and Germany have proposed extending the EU to include common defense, but as of today it had not yet been ratified by either the European Council or the member states. See, e.g., the Treaty of Lisbon. (Note that the Treaty of Lisbon technically removes the unanimity requirement in place of a "double majority" threshold (meaning >55% of vote from >65% of countries) beginning in 2014.)
Fun factoid: France lets Switzerland use part of its territory to defend Geneva. And also let it fly its plane over FR territory because CH is so small that it's not practical for pilots training.
Nobody said anything about motive because there is no realistic motive. These 'assumptions' you're seeing are wholly in your own head.
There is, however, real deterrence, and it's interesting to explore its shape.
..."The Hague Invasion Act,[3][4] since such freeing of US citizens by force might only be possible through an invasion of The Hague, Netherlands, the seat of several international criminal courts and the seat of the Dutch government."
See: http://en.wikipedia.org/wiki/American_Service-Members%27_Pro...
e.g. The UK had plans involving "shooting guards at American nuclear weapon stores in England if they proved uncooperative"
http://www.independent.co.uk/news/uk/this-britain/in-the-eve...