Lukashenko is dead either way if Putin loses. It does not really matter whether they join or sit out. The moment he loses Russian nuclear shield, he will get deposed and brutally killed like Gaddafi. As we can see, he is not dumb enough to try and play sides there, he must support Putin and pray he wins to have a chance at survival.Belarus joining is huge. If Russia really was as hard pressed as some pro Kiev people were claiming, there can be no circumstance where Belarus would join. While Russia can always do a nuclear ultimatum if they're defeated, Belarus runs a real risk to be colonized if they get defeated. So evidently Lukashenko has information which the public does not know which caused Belarus to take this decision.