So far, it ain't happening. European countries are not interested in maintaining large standing armies and more and more third world countries are exploring ways to avoid doing the bidding of the US.
Where would you recruit the Colonial Army? "When the abyss stares at me, it wets its pants." Brian Hopkins
Since the primary interest of the U.S. (and Europe; don't kid yourself that Europe has a significantly different set of interests than America) is to keep the oil flowing, the way that these small countries could distance themselves from America would be to stop selling oil. But they don't.
This is the same deal the Roman Empire gave to non-citizens within the Empire and barbarians from outside it. The Romans also threw in land in border areas or newly conquered provinces, as an added incentive for surviving veterans. Thus they filled the ranks of the army and strengthened pro-Roman elements in strategic places.
