I recall that when I was a kid the U.S. involvement in Viet Nam was justified by the Domino Theory. We had to halt communism before it spread, or so the thinking (er, party line) went. That theory fell out of favor as the war became increasingly unpopular. Now, however, I think a different sort of domino theory is something quite real to worry about. The Greek crisis looks like the next in the chain. Might it destabilize the economies of other countries in Europe? That sure looks possible. And could China be one of the casualties down the road?