As I’ve just noted, Greenspan warned about irrational exuberance, but he didn’t do anything about it. And in fact, the Fed chairman holds what I beli… - Paul Krugman

The legend of King Midas has been generally misunderstood. Most people think the curse that turned everything the old miser touched into gold, leaving him unable to eat or drink, was a lesson in the perils of avarice. But Midas’s true sin was his failure to understand monetary economics. What the gods were really telling him is that gold is just a metal. If it sometimes seems to be more, that is only because society has found it convenient to use gold as a medium of exchange—a bridge between other, truly desirable, objects. There are other possible mediums of exchange, and it is silly to imagine that this pretty, but only moderately useful, substance has some irreplaceable significance.

For the first time since 1917, then, we live in a world in which property rights and free markets are viewed as fundamental principles, not grudging expedients; where the unpleasant aspects of a market system—inequality, unemployment, injustice—are accepted as facts of life. As in the Victorian era, capitalism is secure not only because of its successes—which, as we will see in a moment, have been very real—but because nobody has a plausible alternative.
This situation will not last forever. Surely there will be other ideologies, other dreams; and they will emerge sooner rather than later if the current economic crisis persists and deepens. But for now capitalism rules the world unchallenged.

So you can take your pick as to which Mundell you prefer; but the Nobel committee basically honored Mundell the younger, the economist who was iconoclastic enough to imagine that Canada, of all places, was the economy of the future--and was right.