The US claim that the invasion and occupation of Iraq was a necessary component of the war on terror has been roundly criticized in both popular and scholarly discourse, while many major US allies were unsupportive. However, the present article argues that the US strategy can be viewed as a rational approach to combating transnational terrorist attacks on the American homeland. By deploying a large, activist contingent of troops in a geographical location relatively close to the terrorists' base of operations, a target country can, under certain specified circumstances, successfully deflect terrorist attacks away from domestic civilians, even if the effect of such deployment is not directly to diminish the terrorists' capacity to launch attacks. The interaction between the target government and a terrorist organization is characterized as a sequential move game, the solution to which identifies the conditions under which a deflection strategy maximizes the expected payoff to the target government. It is shown that the deflection strategy makes most sense when the perceived cost of a terrorist attack on the homeland is high and when the target nation is militarily strong and confident of success, has a relatively small proportion of its domestic population that is sympathetic to the terrorists' cause, and is geographically distant from the main base of terrorist operations. Target countries for which one or more of these conditions are absent might be expected to rationally reject such a strategy.