@codebyjeff @luhmann Must be nice to be able to ignore post-WWII history and political realities when pontificating.
First of all, the US has opposed Europe duplicating NATO (i.e. US) capabilities, don't want the vassal states to get ideas. Also, several of the states involved still dreamed of empire. This meant building a coordinated European defense independent of the US has been impossible.
Second, you're talking as if it's a free ride. The US has milked its political and military might for what it's been worth at every single turn in international politics.
Third, in the aftermath of WWII there was no “Europe”, there were exhausted states who hated eachother's guts. The US and Russia were the ones with factories.
Fourth, the idea of a common Europe standing up for itself as an achievable political goal is still pretty new. Europe has a long history of hating eachother's guts and making war. The EU is something fundamentally new, and has no military arm (hello, US), which also is because many states didn't like the idea of federation.
Fifth, after the cold war ended, many Europeans actually thought we could lower our shoulders regarding Russia. This was wrong, but the optimism and euphoria of the 1990s cast long shadows.
I'm running up to the character limit here, but:
tl;dr: The world is complicated.