The traditional nation-state system set up in 1648 with the Treaty of Westphalia at the end of the Thirty Years' War (remember your world history?) is gradually unraveling, or so many think. It's not only Russia that might disintegrate: it could happen to many states (the political geography and political science term for a country), including the U.S. If it happens here, it will be because, I believe, the U.S. as a separate entity would be irrelevant.
If North America were to become involved in a re-regionalization scheme, it would make sense to form a super-region combining the west coasts of Alaska, British Columbia, Washington, Oregon, and California (perhaps called Cascadia). Some of you might remember the environmentalist novel, Ecotopia, in the utopian and eco-fiction genres, published in 1975, in which Washington, Oregon, and northern California form an ecotopian state. (I remember the plot lacked interest, but the environmentalist theme is important.) Just as it would make good geographic and cultural sense to form a Mexamerica. Each large region of North America might form a new super-region, formed in terms of ecology and economics.
Though, what is more likely, I believe, instead of a re-regionalization of more-or-less separate entities, is that we will end up with a United States of North America (USNA), combining the U.S., Canada, and Mexico, but in a loose confederation, stretching from the Arctic Circle to the tropics, something more like Canada is today, in terms of the federalization of political power (versus centralization of power). There are about 430 million people within the three states today, thus the USNA would be an extremely powerful economic force.
Most states in Europe have secessionist movements. There's the Basques (one million strong) in Spain; Scotland is moving toward greater autonomy (they have their own parliament); Wales is way down the road to complete revival of Welsh language, and on and on. This is part of what's called devolution, the restructuring of political power DOWNWARD in the political system (while there's a concomitant restructuring of power upward to supranationalist organizations such as the UN, WTO, NATO, OPEC, APEC, NAFTA, and all the other regional economic cooperation bodies.) The USNA would exhibit both the devolving and the supranationalizing forms of power movement.