My understanding is that the Crimea, and more specifically Sebastopol, is one of the most strategically important cities to Russia, given its position as the port in the Black Sea. The local population is mostly Russian. If this territory remained in the Ukraine, and the Ukraine became subservient to the Union of European Socialist Republics, then the port would be under the domain of a hostile empire - one that also represents a hostile modernist religious theocracy. Why would anyone in the West expect Putin, or any other Russian politician, to behave differently?
This also has me reflecting back to the Crimean War, which was sandwiched between two other glorious Western Wars, The First and Second Opium Wars. In the Opium Wars, the UK declared war on China for refusing to permit English companies to sell Opium to the Chinese. Apparently it is legitimate to blow peoples brains out with drugs if it makes a good profit. Modern Libertarianism owes its founding to John Stuart Mill who argued that this war was "just", because the Chinese had a right to commit suicide with opium that superseded any governmental jurisdiction. The Crimean War was likewise purely a trade war where France and England allied with the Ottoman Turks against the Russians. But then a religious dispute was sought out as a pretext, and the western atheist politicians sold the Crimean War as a Crusade against the Russian Orthodox devils. Thus, we became allies with Islam against a more or less Christian nation. From my Chinese acquaintances, I know that any mention of the Opium Wars is likely to put them into a state of rage. The same reaction would no doubt be expected when dealing with the Russians over the Crimea.
With all that in mind, we have the leftist western politicians issuing idle threats against Russia. Then there are the right wing politicians who are angry that the left's idle threats don't have any teeth to them. One wants to tease the momma bear while grabbing her cub. The other wants to bite the mamma bear in the nose, while grabbing her cub. Or is there something to else this that I am missing?