Last week’s revelation that over 50 State Department diplomats have formally dissented from the Obama administration’s approach toward Syria—calling for greater use of U.S. military power to put pressure on President Bashar al-Assad—is yet another reminder of how frustrating and demoralizing the policy has been, especially for those of us who played a role in shaping and implementing it.

But that’s not the same as asserting it is all Obama’s fault. Looking back on the course of the Syria crisis, it is tempting to see this only as a story of lost opportunities, serial missteps, and inept decision-making. The outcomes have been truly horrific—as many as 300,000 killed, millions of refugees, the rise of the Islamic State, or ISIS, and a disintegration of regional order that the world will be grappling with for at least a generation. This might seem to be a clear failure of American policy. But when one weighs the possibilities for greater U.S. action alongside competing goals, and the demands of managing trade-offs and risks, it is more accurately a cautionary tale of the limits to American power, or anyone else’s.

Given the threat ISIS poses and how horrific the situation in Syria has become, one must constantly ask what the U.S. could have done differently. Aside from a full-scale intervention like in Iraq in 2003, were there alternative courses in Syria or Iraq? The short answer is yes. One must acknowledge, however, that none of these alternatives would have been easy, may not have worked, and risked making things even worse.

Six possibilities stand out.

The first is whether the rise of ISIS could have been avoided if U.S. troops had stayed in Iraq after 2011. Even if we had solved our disagreements with the Iraqi government at the time (or chosen to trust them)—which would not give Obama the same legal guarantees it had given President George W. Bush to protect American forces—it is hard to say whether a few thousand troops primarily on a training mission could have prevented ISIS. Some critics, especially Sen. John McCain, R-Ariz., vehemently believe it would have made a decisive difference and state this as the reason to “blame” Obama’s policies for ISIS’s rise. Yet over 100,000 U.S. combat troops could not prevent the rise of the early incarnation of ISIS: al Qaeda in Iraq. In fact the U.S. troop presence was a magnet for terrorists.

However, there is no question that had the U.S. found a way to keep a small residual force in Iraq, we would have had greater insight into how badly the Iraqi Security Forces were deteriorating, giving the administration more time to react. This would not have been risk-free—American troops would have been without legal protections and also likely remained terrorist targets. When U.S. troops returned to Iraq in 2014, they did so within an entirely different context, with a new Iraqi government asking for help and openly inviting the U.S. in. Unlike 2011, Obama in 2014 believed he had an Iraqi partner he could work with (and the same is true now in Afghanistan, where an enduring presence will remain). Now, around 5.000 American troops are in Iraq, and they will likely stay for some time.

Second, the administration could have started training Syrian opposition forces when it was first proposed by then-CIA Director David Petraeus (and endorsed by Secretary of State Hillary Clinton, Defense Secretary Leon Panetta, and others) in the fall of 2012. Serving in the Pentagon at the time, I also supported an early training program. But the president had good reason to be cautious, and after his concerns were addressed just a few months later, he decided to move forward with the effort to provide military support to the moderate opposition.

Related: We Never Thought Training Syrians Would Be Easy

Would it have mattered if the U.S. had started training earlier? Even those like me who advocated providing military assistance to the Syrians in 2012 must concede that the difference of a few months would not have changed much. Once the administration decided to provide direct military assistance to the armed Syrian opposition in 2013, it proved not to be enough, leading us to embark on a large-scale, Pentagon-led effort a year later. And when that failed in 2015, the U.S. returned to a more modest, small-scale effort, providing weapons and guidance from special operations forces, which seems to be working better.

We should have greater humility about our ability to train indigenous forces, as I outlined in more detail here. After all, if our massive investments of time, resources, and troops to train forces in Iraq and Afghanistan have delivered mixed results at best, one should have reasonable expectations of what a far more modest investment under more limiting circumstances will bring.

Third, and perhaps most notorious, we in the administration could have enforced the red line in Syria in September 2013 by foregoing the diplomatic opening and using force instead. I’ve argued before that it is flawed to believe the idea that Syria (and our larger interests) would have been far better off if the administration had acted against Assad then – which, by the way, was something I helped plan and advocated for on Capitol Hill. While Obama freely admits the process would not win many style points—by announcing intention to strike, then going to Congress, then seizing a diplomatic opportunity—in the end the administration achieved something that the use of force could not: the removal of nearly all Syria’s chemical weapons, which at that time was one of world’s largest stockpiles. The use of U.S. military force alone would not have made that possible. Recall that the planned strikes would have only addressed a small fraction of Assad’s arsenal.

Beyond the redline episode, a fourth option would have been for the U.S. to initiate airstrikes earlier in the crisis to try to gain leverage over Assad, just as it was prepared to do in order to deal with the specific threat from Syria’s chemical weapons. The administration had come close to initiating strikes several times in 2013-14, only to pull back. If the United States had acted then, it most certainly would have been alone. From the sidelines many urged us to do so, yet no countries were willing to join—even France, who had been with us to enforce the red line, was not willing. At one point the U.S. had approached Arab partners with the idea for them to invoke “self-defense” and ask us to act against Assad on their behalf, but not one would do so. This is in contrast to when the anti-ISIS campaign started in 2014, when an Arab coalition and a few Europeans joined the U.S. military in conducting airstrikes.

Since August 2014, U.S. and coalition forces have bombed Syria every day—over 4,000 strikes—without any consultation or coordination with the Assad regime. To put it another way: where the United States flew, it owned the airspace. Given this, in retrospect perhaps conducting airstrikes in Syria was not the grave risk we feared. Once the U.S. began attacking ISIS, Assad’s air defenses proved no match, and he never even challenged American aircraft. Perhaps his unwillingness to confront us was because we were bombing his enemies; maybe the reason was because by that point his forces were degraded and exhausted. Given how rapidly the situation in Syria spiraled out of control, we should have tested Assad earlier.

Fifth, once the U.S. started conducting strikes in August 2014, it could have taken greater risks in the targets it hit, which could have done more to make Assad wonder whether eventually he would be next. The political and legal basis for the air campaign was that it was against ISIS, not Assad. But even within those parameters, the U.S. could have chosen targets that were near Syrian positions, or operated closer to regime-controlled territory while warning Assad not to engage us. We found that in the places we were bombing, Syrian planes mostly stayed away, establishing a de facto no-fly-zone over parts of the country. So if we widened the aperture of the strikes to areas where the regime was fighting the moderate opposition, perhaps we could have expanded this area further and increased the pressure on the regime.

Obama acknowledges that perhaps he does not do enough to exploit ambiguity, but remains very skeptical that doing so actually works. Since it would not be in our interest to escalate, he did not want to put Assad in the position of calling our bluff. Senior military officials were also vehemently against this idea. Like the president, they asked what would come next, warning of the threat to U.S. pilots and the likelihood of civilian casualties. Yet while we were all wary of mission creep, so was Assad; we should have run the risks and done more to eat away at his sense of security, perhaps gaining some leverage.

Another idea we should have explored more seriously was the “discrete” use of force at regime targets—not some massive, “shock and awe” air campaign, but precise, tit-for-tat actions against things Assad valued (such as his presidential helicopter fleet, or a favorite residence). This could have been done without attribution. For example, it has been widely reported that on multiple occasions the Israelis had proved successful at taking actions against regime targets to eliminate specific threats without escalation. They never claimed credit, but Assad knew what had happened and got the message.

Finally, one must ask if the administration erred by focusing so much on Assad’s departure—and if, as with Moammar Gadhafi in Libya, Obama set for himself the kind of a rhetorical trap he tries hard to avoid, placing too much emphasis on the fate of a single leader, and would have been better off with more flexibility.

As the crackdown in Syria intensified in 2011, the administration initially resisted pressure to call for Assad’s step down. Yet once the administration decided that Assad needed to “step aside,” but do so in a way that was managed, it recognized that it would create a gulf between expectations and reality. The president believes that calling for Assad’s departure is about asserting America’s moral authority. As he told Jeffrey Goldberg, the idea that “if you weren’t going to overthrow the regime, you shouldn’t have said anything” strikes him as a “weird argument.”

Looking back, some of Obama’s top advisers wonder whether they had moved too fast to call for Assad to go—asking if the U.S. would have been better off (and perhaps have had more policy flexibility) if it had stayed silent on the question. Some of my former colleagues now say that, as a practical matter, the U.S. needs to steer away from this kind of “Roman Coliseum” impulse, in which American officials render a thumbs-up or thumbs-down verdict on other leaders.

Yet even if the administration had remained on the fence about Assad, the opposition inside Syria, as well its regional patrons, would not have. It is for that reason that the Assad regime is the essential driver of the conflict, and why one can’t pretend that Assad is part of the solution. Which brings us back to the original dilemma in Syria: the question is not whether Assad should go, but how—and who should take responsibility for the outcome.

To accomplish that goal, one must decide which tools will be most effective—and how to manage the inherent risks and trade-offs. Yes, the U.S. could raise the military pressure on Assad, but how does it do so while managing escalation? If Assad resisted military pressure (as every recent leader from Serbia’s Slobodan Milosevic to Iraq’s Saddam Hussein to Gadhafi proved willing to do), then what?

The administration’s incremental approach to military involvement in Syria has been driven by a desire to help address a problem while also avoiding mistakes. Thinking of the lessons of Iraq War—and the imperatives of what I describe as President Obama’s foreign policy “long game”—not doing “stupid stuff” made sense (after all, who actually supports doing “stupid stuff?”).

It is worth asking whether the costs of incrementalism have been worth it, and whether by acting in these relatively modest ways—starting the Syrian training a few months earlier, maintaining some presence in Iraq after 2011, initiating airstrikes sooner and, once the bombing began, being a little more creative with targets—the U.S. could have avoided or better mitigated the massive Syrian refugee crisis or wield more influence over Russia not to escalate as it did in 2015. None of these steps would have been the kind of game-changer many critics suggest, but even a modest improvement would be good enough. And in retrospect, I think they were achievable without undermining the president’s larger goals.

Yet Obama’s critics both in and out of government have an obligation as well. The assertion that the administration has “done nothing” in Syria—or that it is a singular American failure—is irresponsibly facile.

Each day, thousands of U.S. military personnel are in the fight in Syria and Iraq, whether by conducting direct military action or by supporting partners and allies on the ground, often at great risk. Even more resources are being poured into addressing the monumental humanitarian crisis, and in trying to prod the diplomatic effort along.

Given that Obama’s strategy is premised on sustainability and patience, this battle will be conducted far into the future. In words and actions, Obama has made clear his commitment America’s interests and partners in the region, and to defeat ISIS. But he is equally determined not to ruin our country in the process, or let the problems of the Middle East become the singular obsession of American foreign policy. The challenge is to find the right balance, and the Syrian tragedy proves how hard this can be.

This essay is adapted from the book The Long Game: How Obama Defied Washington and Redefined America’s Role in the World (PublicAffairs, 2016).