I would imagine that there is nothing really that we could do...

Missiles are not designed to leave Earth's gravity well. That would certainly drive up the cost, and there were never any Russians on the moon, so there was never the need. Missle engines are not big enough, and I am pretty sure that the guidance systems are not up to snuff to hit a moving target in space, even if the engines had enough horsepower.

It certainly is possible to make an "asteroid killer" missle (and there would certainly be an upper-limit on the size of target that could be disposed of), but that would require a rather large source of funding, which would seem to kill the idea instantly for something that is likely to be needed once every few million years or so.