The right response

Kudos to the Obama administration -- they got this one exactly right:
That's what made Biden's trip interesting. First, just a few weeks after the reversal, he revisited these countries. He reasserted American commitment to their security and promised the delivery of other weapons such as Patriot missile batteries, an impressive piece of hardware that really does enhance regional security (unlike BMD, which would grant only an indirect boost). Then, Biden went even further in Romania, not only extending his guarantees to the rest of Central Europe, but also challenging the Russians directly. He said that the United States regarded spheres of influence as 19th century thinking, thereby driving home that Washington is not prepared to accept Russian hegemony in the former Soviet Union (FSU). Most important, he called on the former satellites of the Soviet Union to assist republics in the FSU that are not part of the Russian Federation to overthrow authoritarian systems and preserve their independence.
This is exactly the right note to strike. We reached out to Russia, and they refused to make concessions. Now we are making it clear that non-cooperation carries a price, and that we will stand by our allies in every way we see fit.

I must disagree, though, with this:
On a deeper level, Russia once again is shaping up to be a major challenge to U.S. national interests. Russia fears (accurately) that a leading goal of American foreign policy is to prevent the return of Russia as a major power.
There is no problem with Russia becoming, once again, a great power. Indeed, having a democratic Russia that played by international laws would bring a great deal of needed stability to the region, and serve as a needed bulwark against a the growth of Chinese power. But my caveats -- democracy and respect for the international community -- are far from being met; until they are, the US has a duty and a vested interest in preventing a Russian resurgence.