Who violated international law, Russia or the US? We did get UN authority to threaten Saddam Hussein but not to invade. Our country attacked Iraq with no provocation except for threats of nuclear weapons that turned out to be false. We killed probably well over 100,000 Iraqis and around 4,489 American soldiers. What did we gain from that fiasco? Iraq is falling apart with the beginnings of a religious conflict that may produce a civil war.
The Kremlin, on the other hand, is claiming territory that has belonged to Russia for centuries. There have been only one or two military fatalities. The whole imbroglio originated in the overthrow of the duly elected president of the Ukraine, Viktor Yanukovych, by a bunch of hoodlums who have been quoted making anti-Semitic remarks and acting like Nazis. Yanukovych was a corrupt president, but the world is full of corrupt leaders. On the other hand, the parliament in the capital of Crimea, Simferopol, which was duly elected as well, voted to put a referendum on joining Russia to the people; the voters overwhelmingly approved the accession. Remember Woodrow Wilson. He asserted the right to "self determination."
Crimea became part of the Ukraine because Khrushchev in 1954 transferred the administration of Crimea from Moscow to Kiev. At the time, it was considered meaningless. After the USSR collapsed, Ukraine became independent. I was in Moscow at that time and was told by Russians that those living in the Ukraine were "little Russians" who would soon return to the fold. At the same time, the people in Moscow had no doubt that the Crimea belonged to them. Russia has more of a claim to Crimea than does the Ukraine.
The threats and military actions made by the West and the US are frightening. We complain that the Russians are staging military exercises on the border of the Ukraine while we are sending warplanes to the Baltic countries and Poland and are planning war exercises with a pitiable Ukrainian force. Our Vice President, Joe Biden, has been threatening Russia and asserting that the US will defend our Baltic NATO allies.