MELBOURNE ― The international military intervention in Libya is not about bombing for democracy or for Col. Muammar el-Qaddafi’s head ― let alone keeping oil prices down or profits up. Legally, morally, politically, and militarily, it has only one justification: protecting Libyans from the kind of murderous harm that Qaddafi inflicted on unarmed protestors four weeks ago; has continued to inflict on those who oppose him in the areas that his forces control; and has promised to inflict on his opponents in Benghazi and other rebel-held territory.

When that job is done, the military’s job will be done. Regime change is for the Libyan people themselves to achieve.

It should not be necessary to rearticulate and reargue these basic points. But it is. Despite the best efforts of U.S. President Barack Obama, U.N. Secretary-General Ban Ki-moon, and others who have stayed admirably focused and consistent, other voices ― from the right, the left, and the simply muddled ― are now capturing media attention, and are beginning to drown, or at least confuse, the basic message.

U.S. Senators John McCain and Joseph Lieberman, for example, have said that the aim must be not only to protect civilians, but also to drive Qaddafi from power. British Defense Minister Liam Fox has suggested that Qaddafi could be targeted. And from the other side, many commentators ― anxiously or cynically, according to taste ― have drawn parallels with Iraq and other past misuses of Western military power. Many others talk of being drawn inexorably into an Afghanistan-style quagmire.

To clarify the issues, the best place to start is with the two U.N. Security Council resolutions. The first, Resolution 1970, adopted on Feb. 26, invoked “the Libyan authorities’ responsibility to protect its population,” condemned its violence against civilians, demanded that this violence stop, and sought to concentrate Qaddafi’s mind by applying targeted sanctions, an arms embargo, and the threat of prosecution for crimes against humanity.

The follow-up Resolution 1973, adopted on March 17, deplored the failure to comply with Resolution 1970, reasserted a determination to ensure the protection of civilians, and called for an immediate ceasefire and a complete end to violent attacks against and abuses of civilians. Then, for the first time ever, the Council explicitly authorized military intervention by member states to achieve these objectives.

Coercive military action was allowed to take two forms: “all necessary measures” to enforce a no-fly zone, and “all necessary measures… to protect civilians and civilian populated areas under threat of attack.” Boots on the ground ― “a foreign occupation force” ― were expressly excluded.

The language of these resolutions could hardly be clearer in prescribing the scope and limits of what should be done. In the case of enforcing the no-fly zone, Resolution 1973 allows the destruction, by aircraft or missile, of any loyalist jet or helicopter that takes off, any pro-Qaddafi forces’ anti-aircraft batteries or missile-launch sites, and the disabling of any airstrip. And, as for the wider mandate to protect civilians, the resolution allows airborne attacks to knock out tanks or troop columns advancing on Benghazi or other rebel-held towns, and ― should they exist ― concentrations of forces within those areas that pose a direct and immediate threat to Qaddafi’s opponents.

In both cases, some questions do arise at the margin. Is it within the scope of the no-fly zone to take out command and control centers that might direct aircraft? Can it possibly be legitimate to kill regime forces actually fleeing from a protected area, or in some other way posing no obvious or imminent threat to civilians? Should a line be drawn against any otherwise legitimate action against Qaddafi’s forces that would be likely to put innocent civilians at risk?

Beyond these questions, there is nothing to debate. Military action expressly designed to kill Qaddafi or force him into exile, to ensure a rebel victory in a civil war, or to achieve a more open and responsive system of government in Libya is not permissible under the explicit terms of Resolution 1973. Nor is it permissible under the moral first principles of the “responsibility to protect” doctrine unanimously endorsed by the U.N. General Assembly in 2005 in an effort to end mass atrocities once and for all. True, one or more of these results might, conceivably, be the effect of permissible military action, but they cannot be its objective.

It also follows from these legal and moral first principles that once there are reasonable grounds for confidence that the threat to civilian populations has been removed or neutralized (as seems now to be largely the case, at least in the east), military action should cease. Of course, a close watch should be maintained, so that enforcement action under Resolution 1973 can be very quickly reinstated. But offshore-based airborne action, with a sharply defined and limited objective, is much less susceptible to the kind of mission-creep and quagmire problems that often beset intervening ground forces, especially those with an inherently confused mandate, as in Afghanistan.

As the situation in Libya and the wider Middle East unfolds, policymakers are bound to face further acute dilemmas, not least in responding to continuing repression in Tripoli, or the similarly ugly and fragile situations in Bahrain and Yemen. Mustering the cross-cultural political will to give the responsibility to protect real ― and consistent ― teeth will always be difficult.

But, at least in the case of Libya, a vital precedent has been set. The Security Council has written the right script; we must now make sure that we follow it.

By Gareth Evans

Gareth Evans, Australia’s foreign minister in 1988-96, is president emeritus of the International Crisis Group and chancellor of the Australian National University. He is the author of “The Responsibility to Protect: Ending Mass Atrocity Crimes Once and For All.” ― Ed.

(Project Syndicate)