I remember when the situation in Ukraine/Crimea was just unfolding and I was discussing it with a friend. At first his position was "There is no proof Russia is in Ukraine, that is just Western propaganda. What do you think, Putin is trying to annex Ukraine? Come on, that's ridiculous" a few months later, Putin annexes Crimea. All of a sudden, his argument changes to "Well Crimea has a very interesting history, and plus, all the people living there really want to be part of Russia" you can't win with these people. They will keep changing their argument. If Putin annexes all of Ukraine tomorrow, you will see the same changes in their arguments with justifications for his terrible decisions.
Also, you can always bet on them saying something along the lines of "Well the US did X, so that totally validates Russia doing Y"