I know that the wording of the Budapest Memorandum didn't require a commitment but it could have been a basis for "you signed this and by breaking this agreement we have grounds for a defense". A defense pact could also have been made with Ukraine without them being made a NATO member.
> This, and a perfectly reasonable desire not to stumble into a direct and intrinsically risky confrontation with their main nuclear rival
But now the situation is worse, a hot proxy war. By making an agreement with Kiev before the war it would have been Russia who needed to avoid a confrontation.
> For one that doesn't like a diplomatic solution, but an overtly military one.
It might be closer to gunboat diplomacy, but rather that than the senseless loss of life we've had since then.
The thing is -- the response you're retroactively advocating here (aggressive brinkmanship) would have been by definition a major gamble. And it does seem that you're basically assuming that the "dice" would have turned up your way.
Whereas most likely the US/UK mindset was: "Yeah, it could go our way, if we went that route. Or it could trigger a nuclear escalation, either as an intentional response from their side -- or a purely accidental one. The odds for this are quite high -- at a bare minimum 10 percent, according to our analysts, though some say the risk is far higher."
The current situation has a recurring risk of escalation also, of course -- though objectively a far lower one.
I don't think they were thinking about a long-term proxy war at the time (as they generally thought Ukraine would be simply overrun if not defended). But we can be very sure they were thinking about the categorically more important issue of avoiding response that could trigger a nuclear escalation -- especially in very short term.
> This, and a perfectly reasonable desire not to stumble into a direct and intrinsically risky confrontation with their main nuclear rival
But now the situation is worse, a hot proxy war. By making an agreement with Kiev before the war it would have been Russia who needed to avoid a confrontation.
> For one that doesn't like a diplomatic solution, but an overtly military one.
It might be closer to gunboat diplomacy, but rather that than the senseless loss of life we've had since then.