From what I understand, Russia had not deployed their most sophisticated air defenses in Syria. If they do deploy their latest and greatest, Western air forces would have a much tougher time pulling-off a strike like this.
To Tess' question; a conventional war between the US and pretty-much anyone else would be lopsided. The US has conventional forces which are wildly beyond what anyone else has. Russia has
one aircraft carrier, and it's a mess. China is building more carriers, and just sailed a carrier group through the South China Sea, as a matter of fact.
While the US continues to build their new Ford-class carriers, there is a lot of debate about the usefulness of carriers. For example, the Russian carrier, Admiral Kuznetsov, is a bit of a gong show as a carrier (
they lost two warplanes when using it in Syria; not shot-down, just kinda, crashed - this is a carrier that, from Wikipedia, "accompanied by an ocean-going tugboat, as a precaution due to potential propulsion failure."). However, the Kuznetsov isn't exactly what we think of as a pure carrier; it carries twelve Granit anti-ship missiles, which are nasty little devils. In a navy-to-navy battle, it is far more likely that those anti-ship missiles would sink something than warplanes.
The problem carriers have today is those anti-ship missiles. They have long ranges. The Granit is something like 600 Km, which doesn't sound like much, until you put them on a sub. Other missiles have much longer ranges. The warplanes on carriers can't match the longer ranges. Either the carrier stays away, and is effectively useless, or it gets sunk. The US is currently developing unmanned refueling drones to extend the range of their carrier-based warplanes.
However, the powers which have such anti-ship tech also have other tech which makes the whole debate moot. An all-out war between the US and a power like Russia or China would come-down to nukes. Even at that, China doesn't have the same nuclear triad capabilities as the US and Russia.
https://en.wikipedia.org/wiki/Nuclear_triad China's nuclear force is closer in number and capability to France or the United Kingdom, making it much smaller that that of the United States or Russia. Their nuclear force is mainly land-based missiles which include ICBMs, IRBMs, tactical ballistic missiles, and cruise missiles.
They certainly have enough that you don't want to get into it with them, but not exactly 'nuke every last motherfucker' levels of nukes.
Going back to Russia, we have to keep in-mind that while they have a large nuclear arsenal, they don't have conventional capabilities which come close to the US. At this point, China could very-well be capable of slapping-around Russia, conventionally. It all comes down to a simple thing:
http://statisticstimes.com/economy/coun ... ed-gdp.phpYou'll see Canada's projected nominal GDP for 2018 ranked at 10, while Russia is 12. The US and China are 1 and 2 (and there is still a wide margin between them).
Simply put, Russia doesn't have the money to support conventional forces on a scale that is anywhere close to the US. They also have to keep pouring money into their nuclear triad to maintain that backstop. This is why
Putin recently showed-off nuke delivery systems Russia is working on. That stuff costs a pretty penny, and Russia is getting squeezed by sanctions and low oil prices. However, the message is clear - Russia is still a very potent nuclear threat to the US.
Overall, a world war is unlikely for the same reason it's been unlikely since the 1950's - mutually assured destruction. If it started conventionally, the US would quickly gain the upper hand, even against China and Russia combined. Either it would end at the front door of Russia and/or China (just before the nukes fly), or we're all dead.
Note that those Granit missiles can have a small-ish nuclear warhead. What happens if a few of those take-out an entire US carrier group? Does the US then say, "fuck it", and send the nuclear triad to the Russian homeland, or continue as a forces-to-forces battle? What happens if the US starts blowing-up Russian submarines, and Russia feels their nuclear triad capability is about to be compromised?
Scary shit, all around. This is what makes Ukraine, Syria, and the South China Sea so tricky. Hopefully, even if there is a scuffle, it doesn't escalate. Though I loathe Putin, I at least trust him to be rational, as I do the leadership in China. Not so much the other guy.
A quantum state of signature may or may not be here... you just ruined it.