That the U.S. does not have vital national interests in Ukraine will not mean that the U.S. has no national interest in holding Moscow accountable for violating territorial integrity assurances that Russia and the U.S. gave to Ukraine in 1994 in persuading it to give up nuclear weapons. Indeed, if left to take its course, this crisis has the potential to fuel further developments that engage core American national interests.
For example, if Crimea becomes Putin’s precedent for creeping annexation in which Russia-instigated Russian speakers occupy government buildings, liberate a territory and establish a relationship with Russia, where will this stop? Could the 25% of the population in Latvia who are Russian speakers be tempted (or coaxed) to follow suit? (Both Latvians and Russians vividly recall that in 1940 Stalin annexed Latvia, Lithuania and Estonia, nations that regained their independence only in 1991 when the Soviet Union collapsed.)
Russian military intervention in Latvia, even under the guise of special forces in green garb without insignia, would almost certainly be engaged by Latvian military and police. If Russian security forces came to the assistance of their brethren in Latvia, as they would be likely to do, this would mean a direct confrontation between Russia and the U.S.-led NATO.