Geopolitics can remain irrational longer than you can remain alive.

That's incredible. Cribbing.

> What possible reason would Putin have for invading Ukraine?

He said he would, and what would trigger the decision at least as early as 2008.

And many things didn't come to pass. The entire business between Israel and Iran from last year springs to mind (also recall that many feared the Bush administration would seek war with Iran, which never happened). The Cuban missile crisis was resolved, and there was no nuclear war in general during the Cold War. etc. etc.

In the end this is just information-free hand-waving which says nothing about the current situation.