Jack the Potato said:
The US has been preparing for war with the East since WW2. EVERYTHING we've done since then aside from the current War on Terror has been to curb the rise of power in both China and the Soviet Union. The result? The USSR collapsed completely and most of it's military technology has dilapidated to the extent that barely any of it holds up to anything the US has today. China is struggling to catch up, but they've only just now succeeded in acquiring a half-built aircraft carrier, whereas the US has an equal number of aircraft carriers to the ENTIRE REST OF THE WORLD (11). And we're BUILDING BETTER ONES. [http://en.wikipedia.org/wiki/USS_Gerald_R._Ford_%28CVN-78%29] And as many very smart men have said over the course of history, controlling the seas is the most crucial aspect of any major war, and it doesn't hurt to control the air as well (which we would).
... especially when you've got the best tech on the planet backing you up. And I'm not even factoring in the support from our Allies in Europe, Japan, South Korea, and Australia. We would literally kick the shit out of China and Russia's armed forces if such a war occurred. Brush this off as bravado and hoo-ha if you want, but I've yet to meet anyone who doesn't think this is the case.
Pleased to meet you.
Actually, the world today is the result of an interventionist United States that just couldn't leave well enough alone. The Soviet Union pretty much self destructed on its own. We were plenty happy to encourage the arms race; but if we won it, did we get anything at all from the billions spent on the 'Star Wars' or SDI program? The CIA succeeded in toppling a Western-style Iranian democracy in favor of a puppet dictator, created an unnecessary war in Viet Nam, and a number of other unsavory things that don't get talked about much.
Our last unnecessary wars were undertaken by an administration that couldn't be bothered to pay for anything. A direct result of which is that the fantastic army and navy - that I hear so much about in this thread - is about to be under-funded. That will mean that a number of active duty ships will be mothballed. The brand new F-35 Joint Strike Fighter is an exercise in how to build the world's most expensive aircraft. I happen to know that between politically-skewed contracts, over-ambitious designers, and cool new technologies, the cost of the new aircraft is at least 300% in excess of a more reliable design. Simply put; right now, this country hasn't yet paid for the last war, and literally cannot afford a new one.
China, as the largest foreign investor in the United States, as it owns most of the U.S. National Debt in the form of Treasury Bonds, which they use to peg their currency to the dollar. Should the two go to war, a global financial crises could result. Whether or not that happens is up to China's discretion. I suspect that China would err on the side of caution and not destabilize the US dollar. Few Americans know that China also has a large national debt; our news media is very self-interested compared to real journalistic media such as the BBC.
Others here have mentioned that China has little real ability for force projection. They're quite right, up to the point where they make the assumption that China 'needs' to do any such thing. There is nothing in the United States that China wishes to take by force. Particularly not when they can do so through economic means, espionage, cyber warfare, or simply copying patents from the U.S. Patent Office website. China has no issue whatsoever with staying on its own turf. They just fudge the maps every few years to assert that their borders are farther out than everyone had thought. Can't blame them for that, here in America, that's called 'redistricting.'
What China does have is the world's largest air force. And that's why the United States would lose. In most every previous engagement since WW I, air superiority determined the outcome of the conflict. In a Sino-American war, that advantage goes to China. There is no conflict unless the US projects its force, and China has the manufacturing power to replace its entire air force in a matter of days. The U.S. would have to invade China's airspace and consistently beat their aircraft and surface to air missiles. It would be like Germany's invasion of the Soviet Union, but played out at sea. The US Navy of volunteer sailors and Marines would be overwhelmed simply through attrition. Not to mention that foreign wars get unpopular fast in this country, sapping any credibility that future war-mongers might have.
Russia does not have anything that the United States wants. In fact, if the United States were to be given control of Russia free of charge, it would still be a losing proposition. Graft and corruption are very deep-seated, and most authority figures - plus the famous 'oligarchs' - feed off of the machine. Imagine 10 Bernie Madoffs in each province. Russia doesn't much care about the United States either, save for its leadership role in NATO. Putin really just wants to be left alone to sell natural gas to Europe through a marketing strategy called extortion. Yes, he'll fuck with Georgia and other Baltic states once in a while. He does it because he knows he'll get away with it, and he knows that there is very little that NATO will do about it. The European Union cannot even save their own currency; they aren't going to mess with Russia.
Here's the bottom line. The United States cannot win a fair fight against an opponent of the same size. The Union very nearly lost our Civil War, and since that time we have been beating up on smaller countries, with or without justification. Additionally, the U.S. is constantly developing fantasy weapons, rather than practical ones. I wish I was making this up. We even tried to develop a vertical take-off version of the F-35. Anyone who has seen the actual footage of that should realize what a stupid idea that was. Our forces had to re-write the manual at least once in the last ten years, just to train soldiers to fight an insurgency. It is as if we didn't learn anything from Viet Nam.
There's a very popular (though seldom spoken) idea over here that WW II was all about the United States vs. Germany. That's not quite what happened. I would argue that we merely enabled the Allied forces to fight on more fronts, with more supplies, and we brought superior long range bombers to the conflict. I would even allow that the United States caused the Allies to win the crucial air war over Germany. The air war was crucial to crippling German industry.
That last part is something that we cannot do to China. China is much larger, with more people, and a much more stable political system than we have. Not to mention that China has a notorious neighbor, with a 'million-man' army, that would happily lend China a few hundred thousand guys.
A much more likely conflict is another U.S. Civil War.