When two great powers jostle, their allies watch. Not out of enjoyment for the spectacle but out of selfish interest, they monitor the development of that rivalry to decide how to align themselves. Alliances often change following the outcome, real or perceived, of a great power skirmish because small states are averse to seeking protection from a weakened or unwilling patron. Great powers, that is, have to prove that their protection is real, their word trustworthy, and their willingness to be in the arena strong. Withdrawing from a contest is not cost free: the watching allies take note.
The observing small state may be the prize of the particular clash between great powers. It has a direct interest in the outcome of that conflict: the winner keeps it, or acquires it, as an ally. But the spectators of the confrontation are not merely those directly affected by it. Other, more distant states also observe the confrontation to assess how much risk a great power is willing to take—and a risk-averse great power makes for a poor security backer.
Take, for instance, Russia in Syria. The unexpected scuffle between the United States and Russia isn’t just about Syria and the Middle East. It is part of a wider competition for the allegiance of states. Putin made this abundantly clear, suggesting a larger coalition led by Moscow, not by Washington, to oppose ISIS. But the main purpose is not the defeat of ISIS or even the momentary backing of the Assad regime; those are merely means toward a bigger end for Russia—namely, to break from the relative isolation imposed upon it after Russia’s invasion of Ukraine.
The United States so far seems reluctant to compete with Russia in this new geographic theater (as it is also in Ukraine). The risks are deemed high, the payoff is unknown, and the temptation to vacate a messy region is big. Why not leave the field to Russia?
But there are costs to not competing. And they transcend the immediate geographic boundaries of the particular contest.
A small episode of the Peloponnesian War illustrates the challenge of leaving the arena to a rival.
Eight years into their escalating confrontation, Athens and Sparta stared each other down in front of…