Addressing the nation on Thursday, President Obama offered two main justifications for taking action in Iraq. Both are in response to the relentless onslaught by jihadi extremists who call themselves the Islamic State.

Obama approved airstrikes in Iraq to protect U.S. diplomatic and military personnel. He also approved a humanitarian effort to help a small sect now trapped on a mountain stave off starvation, dehydration and a possible massacre at the hands of Islamic State forces.

Obama made the right call in both cases. What’s missing, however, is a longer-term U.S. strategy to fight the Islamic State, as well as to stabilize a region reeling from violent upheaval. To date, it’s been difficult to discern just what the Obama administration’s thinking is when it comes to Iraq.

The president correctly acknowledges that the United States “cannot and should not intervene every time there is a crisis in the world” but that there will be times when U.S. action is warranted.

“When we face a situation like we do on that mountain with innocent people facing the prospect of violence on a horrific scale, when we have a mandate to help, in this case a request from the Iraqi government, and when we have the unique capabilities to help avert a massacre, then I believe the United States of America cannot turn a blind eye,” Obama said.

By any standard, this is the right time. About 40,000 members of an ancient but small non-Muslim sect called the Yazidis are on Mount Sinjar in northern Iraq, facing near certain slaughter from the Islamic State. To let them die would be an affront to humanity. It was critical that the United States airdrop supplies until the Iraqi army or Kurdish Peshmerga forces could rescue them. The administration also made the right call to strike Islamic State forces that were advancing on the Kurdish city of Erbil.

But the effort raises an essential question. Scores of innocents have been killed just this year in the Mideast by Islamic extremists or by government forces, such as in Syria. And the Yazidis aren’t the only persecuted faith. Christians are being killed or chased away from areas they have inhabited for millennia. What is U.S. policy on protecting them?

Is the U.S. military response situational, or part of a broader strategic and even moral framework? Obama needs to more thoroughly explain what will trigger U.S. humanitarian intervention, and to what degree it ascribes the so-called “responsibility to protect” ethos.

Obama did address his approach to stopping the Islamic State. But it’s not likely that the nihilistic extremists, who were too radical even for Al-Qaida, will wait until a more coherent Iraqi government can be formed to take action. The movement is flush with cash, arms, territory and recruits.

The Islamic State has seized Iraq’s largest dam, which could allow it to cut off power supplies or even create a devastating flood. Its vision of a pure Islamic “caliphate” isn’t likely to be contained within Syria and Iraq. It poses a grave danger to the entire region, and thus the world.

Accordingly, there should be a coordinated international response. Ideally, this would be the purview of the United Nations, but the U.N. Security Council is increasingly ineffective, if not paralyzed. Once again, the United States will be looked to for leadership.

This doesn’t mean U.S. combat troops will or should return to Iraq. Obama was clear and correct on that issue. But it does mean that the United States cannot “lead from behind,” as it claimed to do with Libya. Indeed, Libya offers an example of what a lack of U.S. leadership can result in: The nation has all but collapsed into anarchy after ousting leader Moammar Gadhafi.

Meanwhile, the Obama administration’s inability to negotiate a status-of-forces agreement that would have left a residual U.S. military presence in Iraq, as well as its indecision on backing moderate Syrian opposition forces, have undoubtedly played roles in the metastasizing threat of the Islamic State.

Obama understands that Americans are war-weary and that he was elected to end, not begin, a war in Iraq. And he knows that short of total war, even U.S. military might has its limits.

But the force of a unified, multilateral response to the carnage afflicting Iraq and the broader Mideast can stop the Islamic State as well as address Syria and other regional crises. Obama should rally a response commensurate to a danger that becomes more apparent by the day.