Putin has been planning this invasion for years, nothing liz Truss or anyone else says will have any influence on Putin's decisions.
Unfortunately, when he made these plans, he forgot to tell the Ukrainians what their part in his plans were. Faced with the might of the Russian army they were meant to roll over, throw down their arms and welcome the liberating army.
The Ukrainians thought that their part was that of any country's when faced by an unjustified invasion by a foreign army. They mobilised their army, whcih is clearly well trained and well motivated, and set out to drive the aggressor back within its borders.
And so far they are doing it very successfully. Not only that, but all most every country in the world has condemned Russia at the United Nations. Even China, their new best friend, abstained rather than supporting them.
Now as sanctions are brought in and pips in Russia are starting to squeak. Putin is trying to agree negotiations, though as yet no cease fire. He still thinks he can win.
Zelentsky has sensibly not agreed to taking part in negotiatons in Belorus. He would rapidly be drinking poisoned tea, touching poisoned surfaces, or just being arrested and never seem again, but is at least showing willing to negotiate, while Britain and the EU move weapons and supplies to the country via Poland.
Western field weapons are generally better than the Russian equivalent, which is why Putin is rattling the nuclear options.
I think that his own generals and ministers will remove him before that happens. The problem with elderly paranoic dictators is that they tend to end up alienating all their friends .
