Sure...but life isn't so simple. Any society which would undertake pre-emptive nuclear warfare against a non-nuclear opponent...even moreso, an erstwhile ally...would doom themselves. The US survived the two strikes against Japan, but this was a country which had attacked them, committed all sorts of atrocities, and ultimately this was seen as a clean way of shortening the war. Only afterwards was it understood to be less clean than many had supposed. Starting a new war though??
I don't think such grand ethical egoism on a national scale is ultimately sustainable. I'm sure some wouldn't agree with me, and I think the era does impact a little, but still...
Also, how do you know which would cause less suffering and death? At best, this is a guess. Unlike Japan, Russia wasn't a defeated enemy with a leadership lying to the population in order to stave off the inevitable.