I don't know... But if it does it'll be like the last 2 and the U.S.A. along with the allies will just kick ass and win.
Of course, it will be pretty bad. However, if it comes anytime soon - then that happens to be good news for people who are unemployed (like in the US right now are unemployment rate is going up).
I change my first answer slightly. If it came around now, we (the allies) may or may not win.
Sure, the USA, UK, and other countries have the military capibility, technology, and man power to pretty much whipe quite a few countries off the face of the earth (if we wanted to that is - but we don't). Thing is what you do with said power - in the USA (and I'd assume the UK as well, but I don't live there so I'm not gonna say for sure) our military is a defence. Has it been used wrong in the past, yeah.
In which case it depends on who's in charge.
It also depends on the enemy.
Oh, but I don't sense danger coming yet (I have a sense about this stuff - I predicted 9/11 one year and one month before it happened - and people called me crazy too).
However, supposedly the end of the world will bring 3 great wars.
Thing is, the Vietnam and Koren War... Those were pretty big as well.
But when it comes, I'm going underground to develop the perfect way to win... And with the right people I could do it. lol