Anyone that thinks the United States, a country that forms the backbone of the global economy, ensures wars between countries like Iraq and Kuwait (until recently), China and Taiwan, Russia and Chechnya and a tonne of other conflicts dont occur simply through the presence of it's fleets and acts as the world's second-largest functional democracy is a source of instability, is simply full of irrational hate.

U.S.A. Probably.

Iraq wasn't a problem until they made it a problem, Israels a problem because they support that country, they prop up terrible regimes all over the world because they are a little better than the other guy, they finance wars, they condone torture, they put poor farmers in other countries out of business with agricultural subsidies and when they provide aid they provide U.S food rather than buying local produce which is available and they help promote a cycle of famine by making the local farmers destitute with aid. ETC!

Maybe we should see what N. Korea decides to do with its nukes & revisit this in a few months or so...

North Korea.

D:

If we were only to take raw statistics and logistics into account, the US probably creates a fairly big risk merely by being a single point of failure: if it goes down, most of the world goes with it and even those who survive still don't make it out unscathed.

However, politics doesn't happen in a vacuum, nor without people. Throw them into the mix, and the game changes drastically. North Korea ("Give us food or we'll start a nuclear war") emerges as a major threat, as does Iran ("Our nuclear DEATHTOISRAEL programs are DENYTHEHOLOCAUST strictly for peaceful KILLTHEGREATSATAN purposes.") Then you have people like Hugo Chavez ("The US is imperialistic man 12-year-olds in bikinis are hot I must take dictatorial power for the sake of my people I AM SIMON BOLIVAR!"), who aren't as big of a threat as they'd like to believe they are, but still have the potential for major annoyance.

Definitely Brazil.

Whatever country Onyxmeth lives in, because he lives there.

It's because I won't get rid of the Santa hat, isn't it?

France.

Yep! The world won't feel secure until they know they aren't likely to get coal in their Christmas stocking!