Crimea, although given to Ukraine, has, since the collapse of the U.S.S.R, wanted to rejoin Russia. With majority Russian population, and multiple referendums to join Russia again. Also, this wasn't a violent takeover, it was a referendum, a legal annexation. Finally, when the West does it, using force and weaponry, and hailed with hate, it's legal and good. When Russia does it peacefully without war and embraced by the population, it's evil and bad!
Crimea has a population almost entirely Russian. It was not part of Ukraine until 1954. The population wanted to remain in the USSR in 1989. Putin's annexation of Crimea was completely illegal, but Crimea should be a Russian Oblast. Over 90% of the people of Crimea are Russian and Russian Speakers.
Russia signed a treaty in exchange for Ukraine giving up its nuclear weapons that agreed not to violate its territorial integrity.
If Russia wants Crimea so badly then they should have no objections to nuclear rearmament in Ukraine. But somehow I think if we tried to help Ukraine get nuclear weapons Russia would throw a hissy fit.
Russia violated a treaty. There is nothing rightful about that.