by Ian Bremmer.

Simon & Schuster. 306 pages. $26.

 I recall in the mid-1980s the late Sen. Paul Tsongas remarking about the recurrent and incomprehensible tendency of United States foreign policy to do for the Soviet Union what it could not do for itself. Tsongas was an exasperated critic of Republican and Democratic administrations for repeatedly backing the wrong dictators, propping up puppets only to confront their overthrow at the hands of citizens to whom we should have reached out, and pouring dollars down the drain of ill-advised policies and strategies.

Ian Bremmer argues similarly about the dangers of unintended consequences, applying the “J Curve,” a long-standing model for understanding economic behavior, to political and foreign policy forces.

In its simplest form, the J Curve (named for the shape of the line that traces it on a graph) predicts that in certain well-defined circumstances, after a desirable change has been made, things will get worse before they get better. In economics, it applies to a nation’s trade deficit after its currency depreciates. Bremmer argues that it also applies to a nation’s general stability and prosperity after it moves from a repressive form of government toward greater freedom.

Applying the “J Curve” to a collection of case studies of states including Iraq, North Korea and Iran — “Bush’s axis of evil” — Bremmer makes two crucial points: First, the danger is that when this inevitable instability arises on the road to freedom, a government’s leaders will try to counteract it by retreating into the familiar stability of greater tyranny and repression. Or worse, that in the desperate throes of a threat to survival itself, they will become part of a dreaded nexus: failed states that produce and sell weapons of mass destruction to terrorist groups and factions.

Second, invoking the genius of George Kennan’s framework used to navigate and negotiate the dangers of the Cold War, Bremmer urges a U.S. policy of “inducement and containment” based on an understanding of the J Curve, to ease states and their people through the necessary evolution from repression and dictatorship to openness, freedom and civil interaction in a global world.

American foreign policy and its outcomes are on the scaffold of world and domestic opinion. Bremmer urges J Curve thinking as a way to make these policies wiser and more effective. His book may also serve as a guide to voters on election day as they try to sort out which leaders and policy makers will best address complicated issues in unsettled times.