Some think that President Obama’s refusal to mount commit boots on the ground in Syria against the Islamic State (or the Assad regime, for that matter) has left a vacuum into which Russia (as well as Iran) have inserted themselves. As in “Nature abhors a vacuum.” In an article at the National Interest, Paul Pillar writes about how dangerous cliched metaphors — such as dominoes, or the current favorite that he cites, vacuum — are when used in relation to foreign policy.

The vacuum imagery implicitly assumes that there are important attributes of the region that don’t really count unless they involve intervention by an external power, and especially by the United States. It is insufficient attention to the heat and pressure involving what already is in a particular country, and too much emphasis on what external intervention ought to be able to accomplish, that often has spelled trouble, for the external intervenor as well as for people inside the country.

The metaphor further assumes a sort of zero-sum quality to events in the region, comparable to how two bodies of gas cannot move into the same space.

Furthermore …

The imagery takes no account, for example, of how external forces can work together and not just work to push each other out of the same space.

In fact …

… in Syria, external forces working together offer the only hope for de-escalating the civil war there.

“The metaphor,” writes Pillar:

… suggests that the United States is not protecting its interests in a particular space if it is not injecting its military forces into that space. … the way the vacuum metaphor is being used carries the implication that filling a space, whether through military force or other means, is to be equated with advancing U.S. interests. But [trying] to fill a space may entail far more costs than benefits, which unfortunately has been true of some very costly space-filling efforts in recent U.S. history.

Pillar sums up:

… the military is only one of several instruments for implementing a foreign policy, and not necessarily the best one in any specific situation. Some instruments that have no physical analogue at all, such as behind-closed-doors diplomacy, may be more useful and effective.