Unless you're someone who thinks beheading people is an appropriate way to advance a repressive political cause, the imminent demise of the Islamic State is welcome news. But we should be wary of a premature "Mission Accomplished" moment and be judicious in drawing lessons from an outcome that otherwise merits celebration.

Toward that end, here is a preliminary assessment of what the defeat of the Islamic State means, in the form of five questions and some provisional answers.

Was the Islamic State a genuine "revolutionary state"?

I still think it was. Back in 2015, I wrote an article noting the similarities between the Islamic State and other revolutionary movements (e.g., the Jacobins, Bolsheviks, Khmer Rouge, etc.), and I drew some fairly obvious lessons from those earlier historical episodes. Each of these radical movements proclaimed an extreme vision for transforming society, believed the forces of history (or divine providence) were on their side and guaranteed their success, relied on extreme violence to advance their aims, and possessed some capacity to inspire people in distant lands. Yet I argued that the Islamic State was not as dangerous as many people maintained, because most revolutionary movements have been unable to either export their model or even survive for very long, unless they happened to seize control of a powerful country. Fortunately, although the Islamic State was richer than most terrorist organizations, it was still a very weak state.

Why did the Islamic State lose?

For many reasons. The defeat of the Islamic State was overdetermined and should not surprise us. Despite its fearsome behavior and access to some modest oil revenues, it was vastly weaker than Bolshevik Russia or revolutionary France or even most of its immediate neighbors. Indeed, it was able to emerge and seize control of a lot of mostly empty desert because of the power vacuum created by the U.S. invasion of Iraq and the subsequent upheaval in Syria. Once the group established itself in Raqqa and the surrounding territory, its example, ideology and material support could cause a modest degree of trouble in some other places, but its inherent weakness limited its ability to spread its message and put it a serious disadvantage once its neighbors recognized the problem that it posed. Revolutionary movements sometimes succeed because they enjoy the advantage of surprise — as the Islamic State did when it first emerged — but it becomes harder for them to expand or survive once more powerful countries are aware of the danger and take action to contain it. The Islamic State was no exception.

Moreover, the Islamic State's radical ideology and abhorrent practices (including beheadings, sexual slavery and the like) alienated almost everyone, as did its tendency to treat Muslims who did not share its extreme views as apostates. It isn't easy to unite the United States, Russia, Iraq, the Bashar al-Assad regime in Syria, Iran, Saudi Arabia, the European Union, Jordan, the Kurds, and others in a common front, but the brilliant strategists leading the Islamic State managed to do it. And once it did, the pretentious caliphate was toast.

Finally, the anti-Islamic State campaign succeeded in part because the United States wisely let local actors take the lead and did not try to eradicate the Islamic State all by itself. U.S. air power played an important role, as did the advice and training provided by other American units. But local actors with a more immediate stake in the outcome and greater claims to local legitimacy did the hard fighting. This judicious use of American power made it harder for the Islamic State to portray the campaign as a foreign assault on "Islam," especially when most of its victims were fellow Muslims.

So is the campaign against the Islamic State a rare success story for U.S. foreign policy?

Definitely, but hold the high-fives. As readers here know, I've been pretty critical of recent U.S. foreign policy, including Washington's recurring tendency to get into wars it is unable to win. The campaign against the Islamic State appears to be a clear military success, however, and we should acknowledge it as such.

At the same time, Americans should resist the temptation to congratulate themselves too much. For starters, let's not forget that the Islamic State would never have emerged had the George W. Bush administration not decided to invade Iraq back in 2003 and then bungled the subsequent occupation. In helping defeat the Islamic State, therefore, the United States was merely solving a problem it had unwittingly created.

But most importantly the circumstances for defeating the Islamic State were propitious. As noted above, the Islamic State was a fifth-rate opponent that lacked abundant resources, sophisticated military power, or capable allies. Its actions brought into being a diverse coalition united by the shared belief that it had to be destroyed. And the anti-Islamic State coalition also had a clear and straightforward military objective: wresting territorial control away from the group, eliminating as many of its supporters as possible, and puncturing its pretensions to represent "true Islam" or to be the model for the future in the region. Without minimizing the specific military challenges involved, this was the kind of fight the United States (and its local partners) should be able to win and the kind of adversary it should be able to defeat on the battlefield.

We should be wary, therefore, of concluding that this particular success is a model for future conflicts or a vindication of America's efforts to "nation-build" elsewhere. In particular, the conditions that made defeating the Islamic State possible do not exist in Afghanistan, Yemen, or Libya, which is why U.S. efforts there have failed repeatedly.

Moreover, defeating the Islamic State opens up a whole new can of worms, including the fate of the Kurds, Assad's desire to restore his own authority in that part of Syria, the role of Iran and Turkey, and the likely emergence of new jihadi organizations. Defeating the Islamic State is a clear win, but its broader significance should not be exaggerated.

Does President Trump deserve some credit here?

Yes, but far less than he is likely to claim. Donald Trump criticized the Barack Obama administration's policies toward the Islamic State repeatedly during the 2016 campaign, and he promised the Islamic State would be gone "very, very quickly" if he were elected. But the fall of Mosul and Raqqa and the imminent demise of the Islamic State hardly prove him right, because the campaign that defeated the Islamic State was designed and implemented by the Obama administration and Trump did not depart from it to any significant degree. He did give military commanders somewhat greater authority to act on their own, but he did not add significant additional resources or tinker with the Obama administration's basic strategy. He deserves credit for sticking with the approach he inherited, and perhaps to have accelerated the pace slightly, but if he were honest (which he isn't), he'd give his predecessor a lot of the credit, too (which he won't).

Is the fall of Raqqa a major turning point in the campaign against "violent extremism"?

Too soon to tell. When the Islamic State first emerged, the main concern was its ability to serve as a potent "force multiplier," using its resources to spread its radical ideology and to instigate both organized and "lone-wolf" attacks in other countries. Had it remained in business, many feared its successes would lend new legitimacy to a set of dangerous and violent ideals. That possibility was a genuine worry, although one cannot rule out the possibility that the Islamic State would have followed the path of earlier revolutionary movements and gradually moderated its views and behavior over time.

We'll never know the answer to that question, which is just fine by me. Going forward, its defeat may puncture the sense of destiny that attracted some people to its bloody banner, and it may lead more potential sympathizers to question the violent tactics that groups like Al-Qaida and the Islamic State espouse. Let us hope so. In the short term, at least, its defeat will make it somewhat more difficult for die-hard jihadis to plan and implement attacks in other countries. For this reason, the chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford, believes, "We'll continue to see reduction in territory, reduction in freedom of movement, reduced resources and less credibility in the narrative."

Even if that proves to be the case, however, no one thinks defeating the Islamic State eliminates the danger entirely. As the New York Times noted a few days ago, "the organization is far from defeated, and remains far stronger today than it did when American troops pulled out of Iraq." Indeed, some experts — indulging the tendency for threat inflation that is instinctive among many national security types — now worry that the danger is growing in the wake of the Islamic State's recent defeats and imminent demise as a territorial entity. Andrew Parker, the head of Britain's MI5, recently warned that the "threat is multidimensional, evolving rapidly, and operating at a scale and pace we've not seen before."

The central problem affecting the broader Middle East remains the lack of effective political institutions, compounded by repeated and sometimes violent interference in the region by various foreign powers (including the United States). This is true in Egypt, Libya, Iraq, Syria, Yemen, Somalia, Afghanistan, and parts of sub-Saharan Africa, and it is the fear of such a future that has led the Saudi royal family to attempt a radical restructuring of its own economy and political institutions. Political and social conditions in these countries still inspire rage against ruling elite and anger at the foreign powers aligned with them, and, in some cases, that rage leads people to join radical movements and take up arms against their perceived oppressors. Until more effective local institutions are present, the danger from radical extremism will not go away. Creating legitimate local institutions is not something the United States or other outsiders can do, however. Outsiders may be able to help at the margins, but only the people who live there can actually accomplish this task.

Lastly, defeating the Islamic State may be a clear win, but it does not tell us whether we are assessing the threat correctly or whether America's broader approach to the problem of global terrorism is the right one. For more than two decades, the primary U.S. response to terrorism has been to raise the alarm, hype the danger, and respond with force, even though the actual danger that terrorists pose to ordinary Americans is vanishingly small when compared with other dangers. Not only has this committed the United States to open-ended conflicts in many places, but it has also helped poison our politics and distract us from far more serious threats (such as the appalling rate of gun violence — including mass shootings — at home).

Don't get me wrong: I'm glad the Islamic State is headed for the dustbin of history. But there is still a debate to be had over how the United States and other countries should address this issue in the future.

Stephen M. Walt is a professor of international relations at Harvard University.