THE SYRIAN conundrum exemplifies the policy challenges that arise when regimes face political crises and violent transitions under opposition pressures. Syria is not the first such case nor will it be the last. So it may be useful to recall how similar past scenarios have unfolded—and sometimes been managed—in order to draw lessons for Syria and future crises.

One can imagine a range of outcomes in Syria. Most pose considerable risks for the United States, Europe, Russia and Syria’s immediate neighbors. But Syrians themselves are paying the price of this violent transition and ultimately are shaping its course. Still, what the United States does or decides not to do can make a significant difference while the clay of political change is still moist. So it is useful to look at some of the available tools of influence and the considerations that should guide those who use them.

A starting place is to examine the range of possible outcomes from such cases. At least seven can be identified. They include:

(i) a “revolution” in which a more or less coherent new order sweeps away the old as a result of violent struggle (Ethiopia, 1974; Uganda, 1986; Russia, 1917);

(ii) a “velvet” revolution in which the regime collapses amid a mixture of street power, external pressure and leadership splits (the Philippines, 1986; Egypt and Tunisia, 2011; the Soviet Union, 1991);

(iii) bloody, broken-back regime change following prolonged strife as regime elements defect and leaders arrange their exit or are killed (Yemen, 2011; Libya, 2011; Ethiopia, 1991);

(iv) successful repression using scorched-earth tools so that the opposition is defeated (Peru, 1992–; Sri Lanka, 2009; Zimbabwe, 2000–);

(v) drawn-out political stalemate followed by “negotiated revolution” (South Africa, 1992–1994; Burma, 2010–);

(vi) prolonged bloody strife that prompts coercive external intervention and an imposed peace (Bosnia, 1995); and

(vii) prolonged strife that prompts powerfully backed, externally led negotiations leading to an internationally monitored transition and elections (Namibia, 1988–1991; Liberia, 2003–2005; Mozambique, 1990–1994; El Salvador, 1992–1994).

These outcomes may only be stage one of a longer transition process. They do not tell us what comes next. Prolonged stalemate could evolve into a de facto partition of the state into ethnic, regional or confessional rump enclaves as the regime arms its core supporters and the central state loses control of much of its territory (Somalia, Democratic Republic of the Congo). The Egyptian example suggests that velvet revolutions can morph into directions that remain unpredictable for some time, while bloody regime change in Libya has been followed by ambiguous but still hopeful incoherence. Successful negotiation, on the other hand, could produce autonomy arrangements that partially decentralize power while the now more constrained state remains intact (as in Aceh in Indonesia or Mindanao in the Philippines).

If outside states attempt to freeze power relations or entrench political-military groups in open-ended power-sharing structures, they likely will sow seeds of future conflict and distort the chances for organic political development (Lebanon and Bosnia). Powerful local actors—the men with the guns—will often try to game the arrangements that flow from negotiated peace deals and use the trappings of democracy to seize and hold on to power, as in Cambodia, Sudan/South Sudan and Angola. Too often, such negotiations simply reflect the balance of coercive forces on the ground at the time they take place, and unarmed civilians become marginalized.

Therefore, much depends not only on local power balances but also on the timing and priorities of outside powers when deals are done. A “peace at any price” approach might respond to immediate humanitarian imperatives, but it also could entrench the wrong actors, prolonging rather than resolving society’s problems. Above all, the impact of external intervention—both military and political—will depend on the level of commitment that outsiders bring to the follow-on implementation phase after the immediate transition takes place.

AS OF this writing, one can make a few tentative comments on Syria’s trajectory in comparison with these varied scenarios. First, successful repression by the Assad regime appears to have failed. Second, a scenario of de facto—let alone de jure—partition of the country would compound the turmoil already facing the region and thus would find little favor in Turkey, Iran or Iraq. Third, an outright victory by opposition forces that effectively blows away the regime is highly unlikely. Fourth, there is little chance of decisive external combat intervention on behalf of the opposition. Syrian mayhem appears unlikely to prompt a repetition of the kind of NATO/UN military action seen in the Balkans, and Syrian leader Bashar al-Assad knows it.

One implication of these observations is that Syria’s best chance lies in the possibility of an internationally led, negotiated transition that is subject to some measure of external monitoring or peacekeeping (UN/Arab League). The key to such an outcome would hinge on American and Russian negotiators with the assistance of UN–Arab League special envoy Lakhdar Brahimi, the veteran Algerian mediator. To be sure, none of the above scenarios will be an exact “fit” for Syria. Something approaching scenario (vii) may be the best hope.

But hope is not a strategy, and simply declaring that Assad must go is not a policy. Lining up the tools and resources to support something like scenario (vii) requires facing some fundamental choices. One central challenge lies in deciding how much of the Syrian state apparatus can serve as the institutional base for the transition and future governance. Another question concerns the fate of people associated with the government during the decades of rule by the Assads. A further challenge lies in the timing of U.S. engagement with Russian leaders, without whom it is difficult to imagine a negotiated transition to a new Syria. The task here is to mesh the American quest for as much of the right kind of change as possible with the Russian quest for a measure of continuity to protect Russian interests. As pressures mount on the regime, Russian impatience for some sort of arrangement will grow. As casualties mount and Brahimi’s dire warnings about the rising humanitarian toll come to pass, American and Western leaders will be under growing pressure to take further steps. While Syria is not “ripe” for negotiation today, the scenario could ripen usefully. There is also the risk that Syria may not ripen at all, but merely rot on the vine.

The test of statesmanship in such violent transitions is to define the least bad outcome and to select a mixture of diplomatic, economic and coercive tools appropriate to the specific case. This requires a very careful assessment of local and regional players. The bad guys may be evident, but good guys could be hard to find. If so, it will be best to help foster a credible process rather than trying to select winners.

Transitional diplomacy requires leverage, and leverage comes from power, in one form or another. Direct military intervention may be the least flexible option in such situations, for several reasons. First, to paraphrase Colin Powell in the Iraq context, if we break it we may end up owning the result. This is a particular dilemma for the United States because of its vast—if stretched—power resources. Analyzing the so-called values cases of the 1990s—Haiti, Somalia, Bosnia, Rwanda—Richard Betts made a persuasive case that “impartial” intervention is a delusion. As he put it, to intervene militarily is to decide who rules the target state—a reality both when we arrive and when we leave. But nonintervention could simply deliver the society to those who are best armed and organized; in other words, it is another way to decide who rules. We have seen the first principle at work in Afghanistan since 2001 and the second principle in the Great Lakes region of Africa since 1994. Neither example gives confidence that military instruments can be effective when employed in isolation from other policy tools.

Clearly, there has been no appetite for direct, boots-on-the-ground military intervention in Syria. One reason is war fatigue, but another is that U.S. decision makers are not sure who (if anyone) warrants support. Beyond that, U.S. leaders have been wary of assuming responsibility for another regime change in the Arab world. U.S. direct combat intervention is not highly correlated with “success” in the transition cases referenced above.

But the United States and its allies nonetheless hold other tools of leverage and influence. One is economic sanctions designed to wear down and isolate the target regime. But this is an extremely blunt instrument that hurts civilians first and foremost. Another tool is humanitarian aid and lethal assistance provided to opposition forces. Whether supplied through proxies or directly, overtly or covertly, such external aid serves two purposes: it sends a signal to the regime’s backers, and it helps level the playing field. Over time, these tools are part of a strategy of “ripening” the conflict by bleeding the regime.

But such tools by themselves are unlikely to produce a successful outcome. Thus, the answer lies partly in finding sources of borrowed leverage and credibility. Neighboring states, regional hegemons and major powers associated with the regime are the most obvious sources of the needed leverage. Close behind them are regional organizations, alliances and the UN. A few examples illustrate the argument: