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The "caliphate" has fallen.

The Islamic State of Iraq and Syria (ISIS) has not.

So the multinational coalition that conquered the terrorist group's last patch of land in Syria needs to remain vigilant and on the offensive.

The victory is a relief for a region reeling from multiple conflicts, but its significance, given the worldwide threat of terrorism, is global.

Credit can be widespread. In particular, praise is due to indigenous forces in Iraq and Syria, where ISIS once controlled a broad swath of land about the size of the United Kingdom after it blitzed disunited governments in Baghdad and Damascus, whose dysfunction in part created conditions for the group to gain ideological and territorial hold in each country.

In Iraq, after an initially disastrous performance by its armed forces, Iraqi troops (as well as some armed militias) regrouped and took the fight to ISIS, thanks in no small part to crucial help from U.S. forces, whose intrepid leadership helped roll back ISIS gains.

In Syria, U.S. forces also helped advise fighters of the Syrian Democratic Forces, a Kurdish-led entity that was most responsible for the caliphate's fall.

Abandoning these allied fighters would have been morally and militarily wrong, which is one reason why so many responsible Washington leaders from both parties, including former Defense Secretary James Mattis, who resigned over the matter, pushed back so hard against President Donald Trump's sudden withdrawal announcement. Fortunately, the president has mostly backtracked on that strategic mistake.

The Trump administration does deserve credit for continuing the campaign begun by former President Barack Obama, who promised that a U.S.-led coalition would "degrade and ultimately destroy" the jihadist group.

Obama was criticized by some for the deliberate nature of the plan, but the alternative was another massive Mideast commitment, something Americans (including and especially Trump himself) have consistently opposed.

More profoundly, it was important, in fact imperative, that Iraqis and Syrians themselves lead the fight, just as it will be equally important that they lead a more hopeful post-ISIS era.

Failure to do this in 2011 after the Sunni insurgency in Iraq led in part to fertile ground for a group like ISIS to emerge. Syria's continued chaos, particularly given the government's illegitimacy after its homicidal reign, will make it even harder to permanently stamp out ISIS, which is still lethal in several sub-Saharan African nations and parts of Asia, and globally in online calls for sympathizers to carry out terrorist attacks worldwide.

"The collapse of the caliphate is a temporary success," Michael Knights, a senior fellow at the Washington Institute of Near East Policy, told an editorial writer. "We could see a resurgence of IS's territorial control in Iraq and Syria in future years there. It's all about how much effort is put into stabilizing those places and particularly developing effective security forces there."

That will take enduring engagement from the multinational coalition, and especially the U.S. And this in turn will take a more sincere and strategic commitment to coalition-building than the Trump administration has displayed to date. Support for such efforts should be bipartisan, which is an increasingly difficult dynamic in gridlocked Washington.

Biding its time, ISIS "is just waiting for us to make the same mistakes again — 'us' being the U.S., the international community, Iraq and Syria," said Knights.

The world, led by Washington, should avoid repeating those mistakes, and remain engaged in addressing the root causes of terrorism and aggressively fighting it when it emerges.