Europe's military hegemony is long dead. Their armies are some of the best-equipped in the world, but only competent on the defense. They could make a US or Russian invasion absolute hell, but the EU (assuming they could combine) could never recreate the 19th Century global empire scheme. Military conquest is an outdated idea. Political maneuvering and economic domination rules the day in the information age. Currently, the US is king in this battle, and only failure to secure the cyberwarfare front can change that, and Europe's just the same as America in that regard.

TL;DR: No.

did Europe become a country while i wasn't looking?

but even if they tried a joint effort, it would ultimately fail,

Europe is pretty a continent made out of hate.

Britain hates itself, try getting a welsh man to work with a Englishman, or a Scotsmen to work with a Irish man, or a Irishman to work with a Welshman, or a Welshman work with a Scotsmen, or a Scotsmen with a Englishmen (i think u get the idea) the whole of Europe is pretty much that.

Each country is a separate entity, so Europe would never manage to unite to take over the world together. Europe is a continent, with the two strongest countries being France and the UK. Plus, neither the UK or France could offensively fight against over superpowers - the UK is pretty powerful and could probably handle defense, but wouldn't do very good on the offense.

Also, there's a lot of hostility between countries - there is a lot of discrimination in the UK towards Germany and Eastern countries, especially Poland. Did you know, the majority of England loves the USA? Seriously, the UK would try and conquer the world with America and Canada, then try try and take over the world with Europe.

They can't do squat with the financial mess they are in. Especially with one of their money saving plans being to cut back on military spending.

If the US was not on their side then they wouldn't be able to because we are big trade partners.

Not now, but in the near future, especially with Russia, it could become a probability.

The whole European union doesn't have the Air attack capability of the single fleet of the United States