In September 2015, U.S. President Barack Obama, usually so optimistic about the future of the liberal world order, grimly described the challenges to it before the UN General Assembly: “dangerous currents risk pulling us back into a darker, more disordered world.” The threat of the Islamic State (also called ISIS) is only one of those currents, but it is certainly the most immediately threatening, a pseudo-state with an army, access to funding, an appealing religion-based ideology, and the capability to launch, or inspire, mass terrorist attacks anywhere. It is bankrupting those regional states that are trying to cope with it and providing the excuse for a destabilizing Russian regional intervention and a budding axis with Damascus and Tehran.

U.S. officials beginning with Obama have repeatedly stressed that the U.S. mission is not to contain ISIS but to “defeat” and “destroy” it. U.S. Defense Secretary Ash Carter has twice stated that we are “at war” with ISIS. And given the group’s potential for mayhem, this policy is wise. Yet 18 months after the first U.S. troops were ordered to Iraq to counter ISIS, the group has neither been defeated nor, according recently to Carter and JCS Chairman Joseph Dunford, even contained.

More remarkable is that the United States arguably has the means to destroy the group through its current policy of air support, train-and-equip programs to build up local allies, and special forces strikes—but only if they are augmented with at least some U.S. ground forces. Yet the administration has dug in on its refusal to send ground troops to the conflict, even as it begrudgingly taps other types of military power, including special forces advisors closer to the front, high-end special forces raiding teams, Apache attack helicopters, AC-130 gunships aimed at the ISIS oil truck fleet. In his December 6 address to the nation, Obama gave this reason for the ground forces ban: using them would result in a “long and costly ground war.” He continued that “If we occupy foreign lands,” ISIS, “can maintain insurgencies for years, killing thousands of our troops, draining our resources.” In that, he was evoking President George W. Bush’s Iraq war as a warning—a rather compelling one for most Americans, who do not want another such war.

A U.S.-backed alliance of Syrian Kurds and Arab rebel groups, supported by U.S. coalition planes, captured Tishrin dam, south of Kobani, Syria December 26, 2015. Rodi Said / Reuters For those of us who have worked with Obama, his argument comes as no surprise. His skepticism toward military action is manifest in his emphasis on ending America’s wars and his unwillingness in 2013 to act militarily against Syrian chemical weapons use. He best summed up his view in an address to West Point cadets in 2014: “Since World War II, some of our most costly mistakes came not from our restraint, but from our willingness to rush into military adventures—without thinking through the consequences.” The choice is thus presented as a stark one: Obama’s military force with an ultra-light touch, essentially the anti­-al Qaeda campaign of bombing, rare ground raids, and support for local forces (so far, with just limited successes, such as in Ramadi) or a return to Bush’s wars in Afghanistan and Iraq.

If this choice—Obama or Bush—reflects reality, the appropriate decision under normal circumstances would be to opt in with Obama and hope that his indirect and half measures might, in the “long term,” as the administration stresses, take out ISIS. But given that the “dangerous currents” that even the president acknowledges are increasingly strong, times are not normal, at least as we defined the word after the Cold War. In that immediate happy period, we faced no existential threat, our military was unchallenged, the broad architecture of global security was stable despite local threats, and, most importantly, all our military engagements from Bosnia to Northern Iraq were so-called wars of choice. As such, they had to be justified not only by ending violence or pushing back aggression, but by social and political goals as well. Michael Mazarr wrote a definitive account of this process in Foreign Affairs two years ago.

For those of us who have worked with Obama, his argument comes as no surprise.

The apogee of this armed amelioration was Bush’s post-9/11 interventions in Afghanistan and Iraq. He made it abundantly clear to those engaged in the two conflicts that his ultimate justification was not just regime change but societal transformation, even if that required a massive counterinsurgency campaign against the insurgents who didn’t buy made-in-Washington social engineering.

Obama argues that if the United States further escalated its operations against ISIS, in particular by committing ground troops, the country would once more be heading in the same direction. But his arguments distort the recommendations about use of troops, and confuse the use of American power meant to take down a threatening opponent with operations to deal with the consequences of that defeat.

First, most suggestions about U.S. ground troops do not advocate large numbers, but rather an elite force to deal with the particular military situation the United States faces with ISIS. Just as the forces now defending against ISIS are all regional, so would the majority of those on the attack be from the region. But to accomplish the president’s mission to defeat ISIS, ground forces must take its territory and smash its organized forces. The reasons why a huge force of local ground troops allied with the United States in Iraq and Syria has had only limited success in such offensive operations include incompatibility of political objectives; low morale; inadequate leadership, weapons, and skill sets; and an inability to take on dug-in, well-armed, and experienced ISIS fighters willing to die without taking on significant casualties.

This is why many commentators, including retired General Jack Keane, advocate a limited U.S. ground force of several brigades (each of 5,000 combat troops plus logistical support) on standby to provide a rapid, elite reserve ready to reinforce any offensive or to spearhead it if it bogs down. Its mission would not be to take over from local and regional forces, but rather, to augment them. Such U.S. forces, as in numerous other conflicts, would serve as rallying anchors for contributions by NATO forces and some of the better local formations. U.S. units, NATO formations, and high-level local forces have skills in rapid decisive combined arms (infantry-armor-artillery-engineer-air) offensive operations that most of the established regional forces and local militias the United States now relies on could only dream of. Although ISIS has 20,000–30,000 fighters according to most estimates, they are scattered around a Texas-sized perimeter holding against hundreds of thousands of troops surrounding them. Given the generally open terrain, total U.S. and coalition control of the air, and the distances involved, the various scattered detachments cannot rapidly reinforce each other.

Thus several U.S. brigades of 5,000 troops reinforced with other first class NATO forces and equal numbers of the best trained local forces, would likely have near numerical superiority, and massive firepower, airpower, mobility, and logistics superiority, over the ISIS detachments that they would face. Even Obama agreed in a November press conference in Turkey, that the United States could take down ISIS rapidly with U.S. ground forces. He was echoed by Secretary Carter in a Senate testimony the next month.

The administration’s putting U.S. ground forces on the table would have two other positive effects on the anti-ISIS campaign. First, it would end a logical absurdity: The United States asserts that the counter-ISIS fight is its own war, yet it demands that other, far less capable, forces suffer heavy casualties attacking ISIS while it risks not a single soldier beyond a few special forces. That’s not what the country did in Korea, Kuwait, or Kosovo, and such an approach is not likely to attract enough quality forces willing to fight under our direction.

Second, the administration’s stressing repeatedly what the United States is not going to do (especially when polls indicate that most Americans want to see more aggressive U.S. action), signals to friends and opponents that the president is not serious about defeating ISIS. Limiting the means in any specific military engagement gives the impression that avoiding costs or commitments, rather than the mission one set out to accomplish, is the highest priority. In that way, the limitation is allowed to dictate the outcome.

To justify the no-ground-troops policy, the president conjures up the Bush administration’s nation-building experiences, which did involve the deaths of thousands of troops and years of insurgency. But this argument has two flaws. The first: If Obama is serious about destroying ISIS, with or without U.S. ground troops involved, he will be faced with a major “day-after” problem once the group is driven underground. That is exactly what happened after, without ground troops, the United States forced the Soviets out of Afghanistan and destroyed the Qaddafi regime. In short, the “nation-building” argument is only logical if the president really does not intend to do anything more than contain and degrade ISIS.

Second, it is anything but inevitable that the “day-after” problem must be solved with U.S. forces. Although U.S. troops bring unique offensive capabilities to any fight, the first priority in any day-after scenario—holding terrain—can be done with local ground forces, backed by U.S. airpower, logistics, and advisors. As we see today, a heterogeneous mix of first- to third-rate Iraqi army units, assorted militias, local police, Sunni tribes, and various flavors of Kurdish fighters with their U.S. support, are holding ground against ISIS when it can field an army of 20,000–30,000; similar arrangements surely could work against its remnants.

Once Washington treats “defeating ISIS” and “the aftermath” as two separate, albeit linked, operations, then the cost and benefits of using U.S. ground troops to defeat ISIS can be soberly assessed.

A counter to this argument is to raise the “Pottery Barn” principle associated with Colin Powell: “ if you break, it you own it .” This idea gained currency in the debate prior to the invasion of Iraq; if the United States decides on a war of choice, when other options were available, and in the process, destroys a state that was providing at least basic services to millions, the argument went, then the United States has practical and moral obligations to stay on to fix what it broke. But this line of thinking simply does not apply in the case of ISIS. The fight against ISIS is not a war of choice, but one of necessity. Destroying the so-called state—although it would create a governance vacuum in areas where ISIS currently rules—would not create any moral obligation for the United States to stay on as an occupying force.

A day-after scenario involves much more than just securing terrain. It also involves providing immediate relief supplies and medical care to large populations, rapidly setting up local governance, and integrating liberated areas into larger political structures including the Baghdad government in Iraq and whatever emerges from the international peace negotiations in Syria. That all has to be sealed by aggressive diplomacy to win over—or at least neutralize—regional spoiler states and engage the International community, international organizations, and NGOs. The United States, the European Union, and the United Nations all have much experience doing this elsewhere in the Middle East and in the Balkans. There is no need for the United States to play the primary role in this longer-term effort, particularly with a troop presence, unless it is seeking a transformation, along the lines of the goal in Iraq 2003–11, of those areas of Iraq and Syria where ISIS had previously ruled. But a United States wiser from its Iraq experiences would presumably not attempt yet another democratic transformation of a Middle Eastern society in the middle of violence (which was the real reason the country stayed on there).

A car drives past over suspension bridge in the Green Zone in Baghdad, October 5, 2015. Iraqi Prime Minister Haider al-Abadi declared the heavily fortified Green Zone in central Baghdad open to all citizens on Sunday. Ahmed Saad / Reuters Once Washington treats “defeating ISIS” and “the aftermath” as two separate, albeit linked, operations, then the cost and benefits of using U.S. ground troops to defeat ISIS can be soberly assessed. Given the costs, inevitable casualties and unknowns when troops are committed, there is always a downside risk that things will go wrong, and perhaps in a happier period where no security issue is truly important the United States could afford to live with ISIS and avoid a risky commitment. But the world is now in another era, one the United States can alas remember. Obama, in his 2009 Nobel Peace Prize speech, summed it up beautifully: “It was not simply international institutions…that brought stability to a post-World War II world. Whatever mistakes we have made, the plain fact is this: The United States of America has helped underwrite global security for more than six decades with the blood of our citizens and the strength of our arms.”

He wasn’t referring just to drones, ordinance launches from 15,000 feet, or 12-man special forces teams.