Both the USA and Russia have serious supplies of gas/oil. That means they won't even have to scramble (too much) to keep their modern tech in working order. The advantage they have over the rest of the world is staggeringly ludicrous. There will be no need for 'diplomacy' over Canada, for instance. Not when a single US warship can, by its lonesome, destroy the entire Royal Navy if it so wishes -- without even taking a single hit, if it really wants to make an effort.
1811, you need line-of-sight just to hit an enemy. 2011, you can obliterate cities from across the planet.
This doesn't mean they'll outright do that, but there will be no question that the ISOTed powers will rule the world. Those who petition to become their loyal vassals first will benefit from trade, and will (over a century or so) become the second-rate powers of the world. Those who try to resist.... are just plain screwed.
Thanks for outlining how screwed everyone else is!
More seriously, though, I'm guessing fracking and expanding drilling are now considerably less of an issue in the US. Not sure what oil politics look like in Russia, but I know that it's a big industry and suspect they'll also make it out okay energy-wise, as you've said. Problem is, they're cut off from their overseas trading partners and either have to rebuild their domestic industries or recreate them out of 1811 nations (i.e. the US losing access to Chinese manufacturing or Taiwanese computer chips). Again, not sure what Russia's trade situation looks like, but given how interconnected twenty-first century supply chains are, I doubt that they're 100 percent fine in the short run, even assuming they can rebuild what they've lost quickly.
In any case, I guess the most "interesting" developments will be in international politics. All the spotlight is now on the US and Russia, both of which mainstream Europe regarded as "outsiders" who weren't fully "like us". Which isn't technically wrong here, either, though they have far more reason to take the uptimers seriously when it becomes clear not just what the raw power disparity is here, but also how the future they came from saw them become sole competitors for global hegemony—whereas the European empires had all vanished. Ditto with the US having a black POTUS, which the downtimers will need to get used to, assuming the "rally-around-the-flag" effect carries Obama to a second term into
2012, sorry, 1812.
So, with the Napoleonic Wars on pause and the US and Russia establishing diplomatic relations with downtimers, who will fall into what camp and what do the next few years (or decades) look like? While it'll no doubt have its reservations about becoming second fiddle, my guess is that France (reluctantly) aligns with the US. His invasion may be overshadowed by the Great Patriotic War in Russia's living memory, but I don't recall Napoleon himself having much (if any) beef with the US historically and he may find it more receptive to a "partnership" of sorts than the Russians. I don't where the other European empires will align, though I've a strong suspicion the British will resent the US for picking off Canada here and overtaking them as the most powerful nation in the world elsewhere, which Putin may try and exploit in true Putinist fashion. Goodbye Napoleonic Wars, hello Second Cold War!