So I imagine Russia knew it was always a possibility that someone would come along and be able to stand up to Victoria, and so they probably planned accordingly...
Well yes, but they've already dealt with that. Repeatedly.
Victoria played a pivotal role in ensuring that the "New Confederacy" or whatever it was actually being called by people who weren't KKK-ers would fall apart into civil disorder and not begin to re-coalesce for a generation or two. Victoria at least
helped bring about the decline of the Pacific Republic/NCR into the form of a Russian satellite state.
The most important tool in Russia's toolbox for the situation "what if an American successor state strong enough to challenge Victoria arises" is "give Victoria steroids until they can beat down the threat." What went wrong for Russia here is...
...
1) California poisoned some of the steroids, by sabotaging the Victorian air force.
2) The Victorians failed to prepare for war. They didn't learn how to properly use even some of the capabilities they had, let alone learn what other capabilities they might need. Steroids alone will not win you a contest if you don't train.
3) The opposition proved unexpectedly professional and competent, particularly in the field of
force projection, something no American successor state except the NCR and Victoria had
ever been effective at after about 2045. Steroids can make you into a Hercules, but if the enemy can get you in a headlock anyway, that matters a lot less.
4) The Victorians went into the operation with a flawed operational plan (dividing their forces and failing to recognize when their diversionary attack had
failed) and flawed logistical capabilities which the Russians had failed to address previously, or worse yet,
coddled.
5) The Victorians underwent a severe case of state fragmentation and collapse immediately after the Detroit Campaign, at which point all previous efforts to steroid-ify the Vicks were nullified by the Victorians setting themselves on fire.
...
But the point is, if we look at past precedent, the Russian strategy for how to deal with a threat to their Plan A has, historically,
not been to have a Plan B. It's been to reinforce Plan A to make it more effective.
I don't know how they'd cope if Victoria were outright destroyed as a state... But realistically, to get there from here we're going to have to batter through a
lot of Russian efforts to continue propping Victoria up.