But a team of Marines and Special Forces that helicoptered in has reported back that, with a corridor off the mountain opened up by U.S. air strikes, the humanitarian crisis is over. The few thousand who remain can be airdropped food and water. The rest can be brought out.
The emergency over, President Obama should think long and hard about launching a new air war in Iraq or Syria. For Iraq War III holds the promise of becoming another Middle East debacle, and perhaps the worst yet.
America would be entering this war utterly divided. We are not even agreed on who the enemies are. Hillary Clinton thinks we should be tougher on Iran and that Obama blundered by not aiding the Syrian rebels when they first rose up to overthrow President Bashar Assad.
Veteran diplomats Ryan Crocker, William Luers and Thomas Pickering argue that Assad is not the real enemy. The Islamic State is, and we should consider a ceasefire between the Free Syrian Army and Assad.
"It makes no sense for the West to support a war against Assad as well as a war against the Islamic State," they write, "Assad is evil but ... he is certainly the lesser evil."
Crocker-Luers-Pickering also argue that the crisis calls for the United States to accept the nuclear deal with Iran that was on the table in July and work with Tehran against ISIS. Iranians and Americans are already rushing weapons to the Kurds, who have sustained a string of defeats at the hands of the Islamic State.
"A new strategic relationship between the United States and Iran may seem impossible and risky," the diplomats write, "yet it is also necessary and in the interests of both. While an alliance is out of the question, mutually informed parallel action is necessary."
If we could work with the monster Stalin to defeat Hitler, is colluding with the Ayatollah beyond the pale?
Other arguments shout out against a new American war.
How could we win such a war without the U.S. ground troops Obama pledged never to send, and the American people do not want sent?
Air power may keep ISIS from overrunning Irbil and Baghdad, but carrier-based air cannot reconquer the vast territory the Islamic State has occupied in Iraq. Nor can it defeat ISIS in Syria.
If Obama did launch an air war on ISIS in Syria, our de facto ally and principal beneficiary of those strikes would be the same Syrian regime that Obama and John Kerry wanted to bomb a year ago, until the American people told them no and Congress refused to vote them the authority.
For such reasons, the demand of Sens. Tim Kaine and Rand Paul -- that before Obama takes us back to war in Iraq, or into a new war in Syria, Congress must debate and authorize this war -- is a constitutional and political imperative.
The questions Congress needs to answer are obvious and numerous.
Who exactly is our enemy? ISIS only, or Assad, Hezbollah and Iran as well? Will our involvement be restricted to air power -- fighter-bombers, gunships, cruise missiles, drones? Or should the president be authorized to send U.S. ground troops to fight?
If we are to be restricted to air power, is it to be confined to Iraq, or can it be used in Syria -- and against Assad as well as ISIS?
If U.S. combat troops cannot be used, what are the prospects of expelling ISIS from Iraq? And if we should drive them out, what is the probability they will come back as soon as we leave, especially if we have left them in control of northern Syria?
Is annihilation of ISIS the only permanent solution? How long and bloody a war would that require?
Will the president be authorized to coordinate war planning with Tehran? And if Assad is to become our de facto ally, should we end our support for the Free Syrian Army and negotiate an armistice and amnesty for the FSA?
Congress must be forced to debate and vote on this war, first, so we can hold them accountable for what is to come. Second, so we can force them to come to consensus on just what kind of outcome in this region is acceptable, and attainable, and at what cost.
What will victory look like? What will be the cost in blood and treasure? How long are we prepared to fight this war, an end to which does not today seem to be anywhere in sight?
How reasonable is it to expect that the Kurdish peshmerga and an Iraqi Army that fled Kirkuk, Fallujah and Mosul, will be able to recapture the Sunni regions of Iraq?
Finally, why is this our fight, 6,000 miles away, and not theirs?