History would show you otherwise.
This is part of Ukraine’s lobbying effort for strong preemptive, rather than reactive, sanctions against Russia; Ukraine is arguing that Russia can be dissuade from invasion by tougher pre-general-invasion action, and is acting (whether they believe it or not) like they believe that their lobbying effort to Western powers for this approach will succeed in getting the desired policy which will, in turn, dissuade Russia.
So far, whether or not they are right that it would work, they seem to be largely unsuccessful in lobbying, with the US, especially, offering only limited sanctions for the actions related to the separatist regions but holding back the massive general sanctions threatened in case of a broader invasion as a reactive contingency.
Ukraine’s official channels are very clear that they view decisive factor in Russia’s decision making the strength of immediate Western action.
Examples: https://twitter.com/DmytroKuleba/status/1495922056541753349?...
Viewing the Ukraine statements about not expecting a full-scale invasion without this context is...misleading. They are saying if an invasion happens, it is because the West failed to be resolute in the ways Ukraine expects them to, not that Russia does not intend to invade.
Well, a couple hours later and this part is outdated, as the US has now announced the first set of general sanctions on Russia and described existing Russian actions as the beginning of the invasion that was always described as the triggering condition for such sanctions.
Yes, they think an invasion already is ongoing, but that's explicitly not the only factor in their call for action. It is directly tied to impact on Russian escalation.
Not all of it.
First, he is a politician. My rational explanation for his words is to cooldown the emotions. Back in last week, you could see news about many oligarchs departing the country, while others trying to cash out every asset they have. Standing enemies at the borders is economically tragic for the whole country. Trying to sell other, non-catastrophic vision is his duty.
Secondly, there were many variants of the invasion. The full-scale operation often means the Russia forces will attack the entire Ukraine - eastern, central and the western. Many experts say this scenario is highly unlikely, because there will be too many casualties on both sides.