IN ITS EAGERNESS to avoid exercising U.S. leadership on Syria, the Obama administration is offering a grim and deterministic analysis of the situation there. “There are only three outcomes,” the U.S. ambassador to the United Nations, Susan E. Rice, said Wednesday.

One, she told MSNBC, is that the U.N. diplomatic initiative of Kofi Annan will succeed, “but that is not the most likely scenario.”

The second is for Russia to support greater U.N. pressure against the regime of Bashar al-Assad — but that, too, Ms. Rice conceded, is not happening.

That leaves what the U.S. ambassador called, in another press appearance, “the most probable” outcome: “The violence escalates, the conflict spreads and intensifies, it reaches a higher degree of severity, it involves countries in the region, it takes on increasingly sectarian forms and we have a major crisis not only in Syria but the region.”

Unhappily, we believe that Ms. Rice is absolutely right on that last point: We have been saying for months that the conflagration she describes is the most likely result of the Obama administration’s strategy of relying on the feckless diplomacy of Mr. Annan or an unlikely rescue from autocratic Russia.

But why are there only three possible outcomes? What’s conspicuous about Ms. Rice’s statement — as well as a similar one Thursday by Secretary of State Hillary Rodham Clinton — is that it excludes any scenario that involves action by the United States. The Obama administration portrays itself as helpless, at the mercy of Mr. Assad and Russian strongman Vladimir Putin. If the former declines to stop slaughtering his people and the latter refuses to stop supporting him, well then — what Ms. Rice calls “a hot regional war in one of the world’s most sensitive areas” is unavoidable.

That’s where we differ. In fact there are steps the United States and its allies could take to head off the conflagration Ms. Rice describes — or at least to temper it. They are not guaranteed to succeed, but they are more likely to bring about the demise of the Assad regime, to prevent sectarian conflict and to stop a regional war. They also will do more to protect vital U.S. interests than a policy of passivity.

The first of these would be to recruit a coalition to create safe zones along and eventually inside Syria’s borders with Turkey and perhaps Jordan, close U.S. allies that already harbor tens of thousands of Syrian refugees. These areas could be defended by air power or by a modest force of Turkish troops; the Turkish government has expressed support for safe zones. With only a handful of loyal military units, the Assad regime would be hard-pressed to challenge the zones while maintaining control over the rest of the country. They could become an area where opposition forces could organize and train, with the help and influence of Western governments. Some experts believe that their very creation could cause the regime to crumble; at a minimum, many civilian lives could be saved.

A lesser option would be for the United States to begin supplying opposition forces of its choosing with weapons and intelligence. The administration argues that this would intensify the fighting — but it is already predicting that the fighting will escalate in any case. If that is to happen, better that pro-democracy forces — which, as White House press secretary Jay Carney correctly noted, compose “the vast majority of the Syrian opposition” — look to the United States for help rather than to Saudi Arabia and other Arab sponsors with sectarian and Islamist agendas.

Pursuing these options would require President Obama to abandon his passivity, to spend political and diplomatic capital, and to set aside his campaign boast that “the tide of war is receding” in the Middle East. But if he does not do so, that tide will swell — and the cost of stemming it will steadily grow.