Before one engages the question of what was possible, it makes sense — and is very clarifying — to address the question of what was most desirable. And on this score, it seems to me any realistic examination of costs and benefits would find that it would have been far more preferable to take care of the Soviets at the time. It would have saved lives, reduced misery, unleashed prosperity, diminished fear and improved the lives of millions if not billions of people for two or more generations in innumerable ways. Contrafactuals are often childish because we never know what resides behind curtain number 2 when we retroactively decide we shouldn't have opted for curtain number 1. But, it doesn't seem unreasonable to say that if we'd forced regime change on the Soviet Union in, say, 1946, that there would have been no Vietnam and, perhaps, no Korean War and no permanently Red China (which alone would have reduced the pile of 20th century corpses considerably). Eastern Europe would not have been immiserated and enslaved. While the space program would have suffered without the Space Race, it seems a sure bet that the net gain of liberated human genius would more than have compensated for that.
The reason this is important is that there seem to be lots of people who think the Cold War was not merely the best we could get, but the ideal policy option period. It wasn't. The Cold War consensus agreed to kick the can down the road for half a century, leaving open all sorts of terrible possibilities regime change would have foreclosed. It maintained a balance of terror, and wrote-off millions of decent freedom-loving people to economic misery and political tyranny and warped our own politics and economy in not entirely healthy ways.
I certainly don't disagree that the Cold War was very, very bad for America in myriad ways, but I’m skeptical about Jonah’s formulation that we should always address the question of what’s “most desirable” before engaging the question of what’s actually possible. Yes, considering the ideal outcome can be clarifying in some cases, but it’s just as likely to degenerate into an exercise in fantasy politics. Of course it would have been desirable for the U.S. to find some relatively low-cost way to “take out” Russia’s Communist Party in the late 1940s and install a more democratic, pro-American government in Moscow; of course managing this trick would have spared our country, and the world, countless miseries over the next five decades. (Though the law of unintended consequences is a harsh mistress, and a different set of miseries might have come rushing in to fill the breach.) But low-cost regime change in late-1940s Russia was so far outside the realm of possibility (even before Stalin acquired atomic weapons) that I don’t see what’s gained by insisting that we give the ideal outcome its due; I don’t think it’s all that meaningful, frankly, to talk about “ideal policy options” that weren’t really options at all. Particularly since history is littered with policymakers who spent so much time meditating on the awesomeness of the the “desirable” option that they persuaded themselves to ignore all the reasons that it wasn't actually possible and go for it anyway.