Ross muses on our strategic presence in Europe:
This is, I think, a very interesting geopolitical question: To what extent would Europe re-arm if America suddenly stopped garrisoning the continent? I think Steyn is right that the European model - small military, big welfare state - was originally rendered viable by the U.S. military presence. But I'm not sure that's true any more, now that the Cold War is over and the old national rivalries have given way to an end-of-history moment. What "responsibilities of adulthood" would Germany, for instance, suddenly feel compelled to take on if the U.S. closed its bases? A Franco-German arms race seem pretty unlikely; so does a sudden push to re-arm against the Polish menace to the east. Putin's Russia is a slightly-more-plausible catalyst for continental rearmament, but only by comparison with the alternatives. Moreover, if you look at defense spending around the world, countries like Germany and its neighbors are already spending much more on their militaries than many nations that live in rougher neighborhoods and don't have the U.S. to look out for them. (The much-mocked Italians, for instance, spend more on defense than Turkey, Israel and Iran put together.) It's awfully hard to imagine the absence of American troops from European soil would cause those expenditures to rise much higher.
What's more plausible, I think - so plausible that I'm just cribbing the argument from lots of other people - is that the overall rate of U.S. spending on defense (rather than the location of our garrisons) is so high and so unmatchable that it drives defense spending down for everybody else (not just the Western Europeans). If you can't compete with the hyperpower, why bother trying? (Especially when you can count on fear of the hyperpower's military to prevent the kind of large-scale cross-border attacks that used to be common, and have now all but disappeared.) The Pentagon's budget isn't just subsidizing Europe; it's subsidizing the whole world. And this would be true no matter where we stationed our troops.
I'm not sure I'm so sanguine that, if we Yanks upped stakes and went home, that the Russians wouldn't become more aggressive in a decade or so; it's very hard to observe the positive effects of our presence, even as the negative effects are easy to see. I don't mean that they would march into Hungary tomorrow; but they're certainly a lot more active, in nasty ways, in former territories we aren't implicitly protecting.
But say this is so. Should we take our ball and go home? What good are the bases doing us?