My fear is not that Putin will suddenly nuke Ukraine, but that he orders the military to engage in more brutal tactics causing far higher civilian casualties and material destruction in Ukraine.

As humanitarian crisis grows, and images of horros reach us in the West, the pressure for NATO to intervene will turn into a tidal wave. Maybe it begins with a No-fly zone, I don't know.

But I think there is a real danger popular opinion will pressure the West to come to the military aid of Ukraine, and once that happens I believe we are in a real danger towards a slippery slope towards nuclear war.

I don't think the nuke buttons will get pushed right away, but a NATO invasion may provoke Russia to escalate further with unconventional weapons: gas, nerve agents, anything that can give them the upper hand when pushed into a corner.

Putin knows he cannot survive an assault by Western powers. He cannot win in the conventional way, which will push him to win in "unconventional" ways whether that is bioweapons, posioness gas, small tactical nukes or whatever.

The specifics are not that important. The point is that the worse weapons he uses, the more we edge ever closer toward a full nuclear exchange. Once we step into that theatre of war, we have to make a red line we do not cross, otherwise we risk playing along on one escallation after the other until there is no more escallations to be had. Only some red buttons to push.