I agree with your main points. I just don’t think saving lives at the expense of national security makes sense. I think national security was the main driver and saving lives was part of the process and part of the calculations.

As for the timing, I think the timing was very interesting from an intelligence perspective. The US was warning about an imminent attack and Ukraine was saying there was no intelligence to support it and then Russia invaded the next day. To me, that says the Russians were testing the West’s intelligence capabilities and launched when they thought they had the element of surprise. I think they were correct and the ensuing first day of battle gave the Russians good intelligence on what was and wasn’t known by the West. It is very useful to know what your opponents know (and what they don’t know), so I think timing was partially urgency and partially opportunity.