The world did not step in in Chechnya, Georgia, the Crimean Peninsula (Ukraine, practice version). The world isn’t going to step in here, and Putin knows it. He spewed the same BS trail of lies each time and faced no actual repercussions. Ukraine is not part of NATO, they aren’t part of the EU. Sure, we sold them a lot of weapons, er, I mean “lethal aid.” And we’ll sanction those darn Russian leaders, so that they can’t go on vacation to as many nice places. But in the end, Russia will take another step toward rebuilding the USSR. Now, I’m not sure that we Could stop them (we being US and Europe), but I don’t see anyone actually doing anything of substance. I am sad today, especially for the Ukrainians.
eta - but at least Putin waited until after the Olympics. If he started the war during the Olympics, it might have looked bad to the US Republicans, the most steadfast defenders of Russia.