It's perfectly possible for the EU to have a war with the US. Wars take time. The EU has better heavy industry, better ability to replace destroyed ships etc.

If we're going to have a war it will probably last at least half a decade, probably a little bit more. What you say of the EU could also be said of the US at the time of the attack on Pearl Harbour in 1941.

If we weren't open to the possibility, we wouldn't be sending tripwire forces to Greenland, as we currently are.