Is tricky, there is massive bullshit on both sides. Ultimately, the Crimea situation is about the Black Sea Fleet. If Putin had lost control of that then he would have been finished. The eastern Ukrainian situation is trickier. Those guys are nuts, but giving them toys must have seemed like an opportunity too good to ignore, until the airliner came down.

Personally I think Putin is addicted to power rather than conquest, but will do conquest if he feels that not doing so endangers his power at home. He is very dangerous, but thankfully he doesn't appear to be an idiot.

Now if Gorbachev had been given proper support when he needed it...