One legacy of Washington’s support for coercive embargoes against Iraq in the 1990s has been a series of U.S.-imposed sanctions aimed at other troublesome countries and nonstate actors. Saddam Hussein’s invasion of Kuwait turned sanctions into a foreign-policy growth industry, at least as far as American diplomacy is concerned. Such measures aim at a wide array of strategic goals, from ending wars and deterring the proliferation of weapons of mass destruction to extraditing international fugitives, controlling the spread of international terrorism, restoring democratically elected governments, and protecting human rights. A new U.S. administration will inherit dozens of ongoing UN, multilateral, and U.S. sanctions. They aren’t all glorious successes. Decades of sanctions against Cuba have proved an abject failure. Current measures against Myanmar and Sudan are barely half-measures. And sanctions on Iran and North Korea appear to be caught in endless bureaucratic red tape.

Our incoming president will face the challenge of handling these complex, difficult-to-manage instruments. He or she will need to be acquainted with the law of unintended consequences. It is generally agreed that the initial sanctions imposed on Iraq led to terrible human suffering. Eventually more finely calibrated measures were designed, including freezing assets of foreign banks, charities, and individuals; imposing travel restrictions; and creating specialized commodity and arms embargoes. Yet critics insist that even these so-called “smart sanctions” have a track record of hurting innocent civilian populations—as has been the case with the October 2007 U.S. restrictions on selected Iranian banks. And half-hearted enforcement in the cases of Sudan, Myanmar, and Zimbabwe has sabotaged what otherwise might have been an effective attempt to improve human rights. Sanctions boosters, meanwhile, note that sanctions succeeded in denuclearizing Libya and in locking down terrorist-support networks after September 11. They also point to substantial success in safeguarding fragile democracies and their electoral processes in Angola and Liberia.

Reviewing these successes and failures should be a top priority for the incoming administration. Six general principles should help guide the way:

In this age of globalization, unilateral sanctions do not and cannot succeed. Multilateral cooperation is essential. When international (UN), regional (for example, EU), and national authorities coordinate effectively to design, monitor, and enforce sanctions, chances for compliance increase. Only those measures grounded in international law and enforced by multilateral institutions have real staying power.

Sanctions rarely work when deployed merely to punish or isolate. While initially they may generate partial concessions, in the long run they tend to create an impasse, if not a crisis, between the states on either side. Putting the economic squeeze on a targeted state is only the first step; the goal is to use sanctions to set the bargaining table, which is where real gains are made. Getting the target to change its behavior requires active diplomatic engagement—even when the target is a pariah state.

Sanctions alone will not alter the behavior of dictatorial regimes or stubborn nonstate actors. This truth often frustrates and puzzles foreign-policy leaders. Yet as the George W. Bush administration has belatedly and reluctantly learned in dealing with North Korea, controlling weapons of mass destruction means using carrots as well as sticks. And this maxim holds even if the only carrot offered is the removal of the original sanctions, as with Libya.

Sanctions are more likely to succeed when the target believes that failure will trigger even harsher actions, specifically military force. This is why sanctions under Chapter VII of the UN Charter should not be imposed lightly. If sanctions come to be seen as a bluff, they are doomed. No U.S. president should impose sanctions simply as a way to “do something.” Sanctions are not instruments for changing regimes, but for changing a regime’s actions; and to be effective, they must detail a very specific set of credible, limited demands. Both sides must understand what constitutes compliance. Moreover, a target state must be confident that changing its behavior in accord with specific demands will produce a timely lifting of the sanctions and the delivery of promised benefits. When those who impose sanctions suddenly shift the rules, as the United States did with Iraq, targets react with defiance, which defeats the policy goal.

Decision-makers must remember that sanctions are only one of the tools available for achieving a larger foreign-policy goal. When sanctions are maintained for so long that they become the policy, they lose effectiveness. This was the trap the United States and the UN fell into with regard to Iraq in the 1990s. The same temptation now looms in the case of Iran.

To implement these strategies, a new administration will need to repair the damaged U.S. role in the Security Council, mending relations with the other permanent members while helping reestablish the legitimacy of the council’s use of sanctions to defend international law. An effective sanctions policy is thus inseparable from a reinvigorated commitment to the UN—which is, after all, the institution where responses to threats against international peace must be formulated and implemented.

Two challenges currently impede effective Security Council sanctions. First, the Iraq war debacle has severely weakened the potential for consensus where such measures are concerned. As a result, the Bush administration has been forced to propose only weak sanctions, ones with limited economic bite. For example, the current U.S.-designed sanctions against specific individuals in the Sudanese government have no prospect of halting the slaughter in Darfur, and everyone knows it. Yet in order to do something, the United States institutionalized this ineffective, even cynical practice.

A second challenge—in fact, a rapidly developing crisis—concerns the Security Council’s authority to shut down terrorist networks via smart sanctions. Creating lists of individuals and entities suspected of terrorist ties has been central to a plan for preventing future terrorist attacks. But such lists have raised concerns about accuracy and reliability; and the United States in its council leadership role has failed to respond to charges of erroneous designation and lack of due process. Faced with no responsive mechanism to guarantee transparency or legal integrity, and no movement from the UN, appellants have turned to European courts, where initial rulings have affirmed that their legal rights have been violated. This situation presents a potentially devastating blow to UN counterterrorism efforts—and, by implication, to the integrity and authority of the council itself.

A new administration will need to delve into this sanctions morass with skill, determination, and integrity. By statement and example, it must renew international confidence that UN Security Council sanctions are fair, uphold the highest standards of law, and aim to reintegrate targets into full status in the international community. Such confidence will likely only develop with the appointment of a new kind of U.S. ambassador to the UN, one whose credentials include respect for the UN, for due process of law, and for human rights.

This essay is part of the Issues 2008 series of commentaries on the important issues confronting the next president and Congress.