48? That sounds like a lot. Isn’t that more than all other nations combined?
Edit: Doh, never mind, you fixed that while I wrote my post.
Why would it need to penetrate anything? Trident II missiles have a range of over eleven thousand kilometres. A Royal Navy SSBN could incinerate every large city in the United States while sitting in the Thames.
In a real war against USA, probably some other countries will join the EU side, like Serbia, maybe Lybia, even Iran, if they think that there is a chance that the americans will lose.
Iran has those long range missiles that can reach further than Turkey, Lybia could make things bad in the Mediteranean Sea if the US navy will get past Gibraltar.
All East Europe except Russia and the Balkan countries will help the EU or remain neutral, because most of them wish to join the EU in the future.
With the EU-US conflict going on, Russia will get a stronger hold of the Caucasus countries like Georgia, because no one will pay attention.
And of course China s economy will go down because EU and USA are their biggest markets, and with a war going on, no one will buy their toys/mp3 players/tooth paste whatever.
Also, in real fighting, with soldiers on the ground, the US will not have a chance taking over one single country in Europe.
P.S. sorry for not being clear enough, English is not my first language.
These questions are always ridiculous.
Relations between the US and EU are so close (even after the recent diplomatic unpleasantness over Iraq between the US and continental nations) that something monumental would need to happen to damage them. In which case, the tension between the two power blocs is going to build over a prolonged period. If you’re assuming that the EU and US are at war with each other, and their defence spending is still set at 2009 levels, then you aren’t exactly being realistic.
All Europe has to do to “win” is to repel an attack. As an example, posters have mentioned America’s huge air superiority advantage. But that’s an air superiority advantage in 2009, not in a world where relations have deteriorated. If there really was a risk of a massive air assault, and a real risk of war, there’d be so many air defence batteries over Western Europe that there’d be more missiles flying around than there were arrows at Agincourt (and our air defences aren’t some third world piece of shit, neither). Western Europe isn’t Iraq: a nation that’s got little manufacturing capacity, wealth, or high levels of technical expertise.
Similarly, it’s impossible to take nukes off the table. If there was a risk of the UK or France being invaded, nukes would be used. That’s what they’re for.
Iran’s rocketry expertise is nowhere near as developed as Europe’s. If we’re relying on Iranian rocket technology, Lord help us all.
I know that they are not as developed as EU, but they still inflict damage, and they can be considered as a threat. Anyway, we would welcome any help against the American threat 
I like this kind of questions, it reminds me of when I was a kid and was arguing with my friends over who would win a fight between Bruce Lee and Jackie Chan, Spiderman and Batman, etc
Who is ‘We’ ?
BTW…it’s fairly obvious that the winner of a fight between Lee/Chan etc would be won by whoever has the light sabres and/or a small chunk of Kryptonite should Superman poke his nose in
You don’t like what-if games do you…
You probably shouldn’t post in those threads.
Changing the OP and answering your own changes and then calling other posters who played with the OP stupid will not gain you friends and influence people.
Just like a silly Euro… 
Europeans. I was speaking for all of them. Except the Belgians.