Sorry, what was the one principle? The US certainly didn't stop randomly invading countries after WWII.
The US didn't stop invading, and neither did the USSR. But the one principle was that waging war for territorial gain is no longer acceptable.
After WWII, the major countries understood that while it's impossible to completely outlaw war - states will find real or imagined reasons to attack each other - if we agree to freeze borders, most of the motivation for waging war will go away.
And it worked. After 1945, no developed country started a war against a peaceful neighbour to perform a land grab. The very few exceptions where annexations did happen were in the context of pre-existing state of war, and even so were not recognized by the international community (e.g. the Golan Heights).
But actually invading a country which doesn't threaten you and annexing part of its territory? Didn't happen after 1945.
Until 2014. Welcome to the new era.
Why is this the only one principle that is relevant? Doesn't grabbing natural resources & other assets [1] constitute as a kind of territorial gain? Why is anything UN related relevant now when it wasn't relevant when the United States was invading Iraq?
>"But actually invading a country which doesn't threaten you and annexing part of its territory? Didn't happen after 1945."
At least the first part of this statement is factually incorrect. I can't think of how Iraq that is nowhere close to the United States was a threat to it. Doesn't destroying an independent country's government and installing your own chosen leaders count as some kind of territorial grab? Sure that isn't the definition of annexing, but if I'm ruling your country and calling it by its old name, what is the difference?
[1] O&G in Iraq :: most lucrative contracts to American O&G giants. Similar for some other industries in the country.
http://en.wikipedia.org/wiki/United_Nations_Security_Council...
On September 16, 2004 Secretary-General of the United Nations Kofi Annan, speaking on the invasion, said, "I have indicated it was not in conformity with the UN Charter. From our point of view, from the charter point of view, it was illegal."[1]
Territorial wars, not just any invasion or a military op or a coup or installing a friendly regime. The very fact that you don't see much difference shows that the world has forgotten how terrible they used to be.
The fact is that al most no one got killed when the Russians went in. The same cannot be said about the wars we have ventured into.
It's true that the majority of Crimeans are Russian, but the majority of people in Sudetenland were Germans, too.
The whole point of territorial integrity is that state boundaries are frozen to prevent territorial wars, even if they don't happen to coincide exactly with ethnic boundaries (they never do).
If there's no threat of territorial land-grabs, there's no motivation for the sovereign power to do ethnic cleansing. In Crimea, for example, Russians were and remained the majority since Ukraine declared independence in 1991. Ukraine never tried to settle a huge mass of Ukrainians in Crimea, or induce Crimean Russians to move out. In the bright new world we've now arrived at, states will be very motivated to "smooth out" their populations by ethnicity, so that neighboring powers don't invade and annex lands with "their people".
The 19th and 20th centuries were rife with such ethnic cleansings and mass resettlements; ever since the fallout of WWII we had very few. Not anymore.
There's less motivation. If power is (or might be) democratically controlled, and issues are divided along ethnic lines, then there remains motivation.
Still an important point, though.
It wasn't tolerated and eventually corrected, but it still happened.
See anything like that happen with Russia's annexation of Crimea?
What you are describing as a first with Crimea in 2014 had, in fact, happened before in a similar way. It's just with Crimea so far there's been much less bloodshed.
There's a difference between saying such actions have not been tolerated since WW2 and such actions have not happened at all.
* Attack Russia?
* Try to force them to submit with sanctions (current line)?
* What else?
A real economic and financial isolation would weaken Putin's regime immensely, and probably topple it quickly. One thing which is very different from the Cold War is that almost everything Russians consume is manufactured outside its borders (and if China doesn't play along, that would only reduce the pressure so much).
There's real and very high economic cost to implementing such sanctions. Europe is only just now slowly recovering from its depression, and the US has plenty of problems with its "jobless recovery". Real sanctions might hurt a lot. But if you really, truly want to stop a new Reich in process of ramping up, and I do not use that word lightly, that might be the price you should be willing to pay.
The above is the most extreme version, but even much weaker sanctions would be way better than the pathetic travel bans on a dozen-odd individuals.