Frustrated with the United States’ slow progress against the self-proclaimed Islamic State (also known as ISIS), Iraq is flirting with the idea of taking on Russia as its primary partner in the battle. The Iraqi military announced last week that it had reached an intelligence-sharing deal with Iran, Russia, and Syria. Haider al-Abadi, Iraq’s prime minister, recently said that he would be open to the idea of allowing Russian air strikes in Iraq. And the highly influential Shiite cleric Ayatollah Ali al-Sistani called for greater international involvement in the fight against ISIS, hinting that he, too, would welcome Russian support.

Iraq has a history of seeking additional weaponry from Russia whenever it believes that U.S. efforts have fallen short. In 2013, former Prime Minister Nouri al-Maliki signed a $4.2 billion arms deal with Russia after the United States delayed the delivery of F-16s to Iraq, partly out of fears in Washington about how Maliki was planning to use the jets. And after an apparently unsatisfactory trip to the United States in April of this year, Abadi traveled to Russia to appeal for more arms—a request that the government of President Vladimir Putin granted.

The Iraqis have increasingly come to prefer dealing with the Russians. One source from the Iraqi Foreign Ministry complained to me of the U.S. insistence on training Iraqis in the use of antitank missiles, which, the source scoffed, “ISIS farmers can figure out how to use.” He added that the Russians would never insist on such patronizing restrictions. Russian Foreign Minister Sergey Lavrov confirmed as much on September 27, when he told Russian press that his country was prepared to supply Iraq with modern weaponry without presenting any political conditions—unlike, he said, other arms suppliers.

Russian President Vladimir Putin shakes hands with Iraqi Prime Minister Haider al-Abadi during their meeting at the Kremlin in Moscow, May 21, 2015. Kirill Kudryavtsev / Reuters Iraqi Defense Minister Khaled al-Obeidi went even further during a visit to Moscow earlier this year, in which he said that “in the battles we are fighting now, Russian weapons have proved themselves as the very best. I know that the Americans can’t supply us with such weapons,” adding that the Russians are better able to deal with a “war of attrition” in which Iraq needs continuous and large infusions of arms. Beyond the formal military establishment, Iraq’s Shiite militias have also been vocal in their support of Russian intervention, with a senior figure in the Badr Brigade saying that the group would “strongly welcome” Russian air strikes in Iraq. A spokesman for Asaib Ahl al-Haq said that the group fully supported Russia’s increasing role in the conflict, because the United States is “not serious” about defeating ISIS.

But betting on Russia would be a colossal mistake for Iraq. The Russians would likely go in hard and strong, as they are doing in neighboring Syria, with little regard for civilian casualties and without a strategy to deal with the political drivers of the conflict. Although the heavy bombardment of ISIS positions may be satisfying in the short term, it is likely to exacerbate the conflict in the medium term by alienating the Sunni civilian populations currently trapped under ISIS rule.

The Barack Obama administration has the right plan for liberating Iraq from ISIS, but it has been too cautious in its execution. To make progress in this sluggish war, win back the confidence of its Iraqi partners, and stave off another Russian intervention, the United States should double down on its strategy to defeat ISIS.

The U.S. military strategy in Iraq has been driven by the belief that long-term success against ISIS requires the buy-in and active participation of local Sunni communities. Based on the lessons from the 2007 Sunni Awakening, during which an estimated 100,000 Sunni tribal fighters joined forces with the United States to drive al Qaeda out of Sunni territory, U.S. forces are painstakingly trying to rebuild relationships with local Sunnis. In fact, a key reason that the Obama administration decided, on June 10, to send 450 additional troops to Iraq was to encourage more Sunni tribal fighters to join the battle.

The United States is in the best position to act as an honest broker between fearful Sunnis and skeptical Shiite soldiers.

American troops are also venturing beyond their bases to accompany Iraq security forces during so-called key leader engagements ­—that is, meetings with tribal leaders. The wars in Iraq and Afghanistan have taught the U.S. Army to place a premium on face-to-face meetings with key leaders that build trust and garner support—among both the leaders and Iraqi security forces—for the U.S. mission. This is the right approach, but it should be taking place on a much larger scale.

The United States is in the best position to act as an honest broker between fearful Sunnis and skeptical Shiite soldiers, and it should be intensively investing in doing so in Iraq. Russia could never play such a role in Iraq; its long-standing support of Syrian President Bashar al-Assad during his mass slaughter of Sunni civilians in neighboring Syria has permanently destroyed Sunni trust in the Russian government. The Awakening movement in 2007 worked only because Sunnis put their trust in the U.S. military to be the guarantors of their safety, and the United States can persuade significant numbers of Sunnis to join the anti-ISIS fight only if it can once again present itself as a credible intercessor with Baghdad. But there are far too few U.S. troops in Iraq for them to gain the confidence of frightened Sunni communities. The deployment of an additional 10,000 soldiers would go a long way toward achieving this goal.

The United States has, correctly, decided that earning the trust of Sunnis also requires the relegation of Shiite militias to a secondary role in the military campaigns against ISIS, and it has kept Shiite militias at arm’s length in Ramadi. After the revenge killings and attacks by some militia elements during the assault on Tikrit and its surrounding areas, the United States has been vocal about the need to prevent Shiite militias from exacerbating sectarian tensions during the battles in Anbar province. This is absolutely the right policy, but without ratcheting up its own attempts to build a Sunni fighting force that is both willing and capable of fighting ISIS, the result is a dramatic slowdown in the campaign against the militants. Beyond its rejection of militia involvement, the United States has also been criticized for overcautious use of air strikes and for its slow and insufficient delivery of military equipment to Iraqi armed forces.

As for the delivery of weapons, it is just as important that the Iraqi army be able to successfully use the weapons that the United States has already made available as it is to continue providing further equipment.

When it comes to air strikes, caution is indeed warranted. In this war, the outcome is deeply dependent on the perceptions of the civilians trapped under ISIS rule, and the United States cannot afford to alienate those civilians. The United States and Iraq can make progress, though, by ramping up the training of Iraqi air controllers and by allowing U.S. air controllers—or joint terminal attack controllers (JTACs)—to accompany Iraqi forces onto the battlefield so that they can call in air strikes.

For several months, the Obama administration has been considering training Iraqis as air controllers to call in U.S. air strikes as a way to speed up the air campaign. But it is worried about the risk of misidentification of targets, the language gap between Iraqi soldiers and American pilots, and the time it would take to train Iraqis. This risk has been tragically highlighted by the U.S. air strikes allegedly called in by Afghan forces on a Doctors Without Borders hospital in the town of Kunduz in Afghanistan on Saturday. But despite such risks, if the United States wants to regain the momentum in this war, it must deploy JTACs with Iraqis into battle and train Iraqis to take on the air controller role themselves. Without the capacity to call in accurate air strikes, the United States is giving away one of its biggest operational advantages against ISIS.

The Iraqi Counter Terrorism Service forces participate in a training exercise at the Iraqi Counter Terrorism Service Academy on the Baghdad Airport Complex in Baghdad, Iraq, July 23, 2015. U.S. Defense Secretary Carter made a surprise visit to Baghdad to assess the campaign against ISIS. Carolyn Kaster / Reuters As for the delivery of weapons, it is just as important that the Iraqi army be able to successfully use the weapons that the United States has already made available as it is to continue providing further equipment. After the fall of Ramadi to ISIS in May 2015, Obama ordered the expedited delivery of weapons and equipment to Iraqi security forces, Kurdish peshmerga, and Sunni fighters. The weaponry is geared toward the specific challenges that Iraqi forces face, including the deadly use of improvised explosive devices, or IEDs. The Iraqis have received, and are conducting counter-IED training with, binoculars and GPS devices to identify and mark IEDs, as well as equipment and explosives such as breaching systems and mine rollers to clear the IEDs. In addition to counter-IED equipment, the Iraqi security forces are receiving shipments of tanks, helicopters, individual weaponry, and body armor.

But the overstretched Iraqi army is struggling to absorb some of this equipment. For instance, the United States has offered to send the Iraqi army mine-resistant, ambush-protected (MRAP) vehicles, which are combat trucks that are resistant to the IEDs regularly deployed by ISIS. But of the more than 3,000 MRAPs being made available to the Iraqis, the Iraqis have accepted only 300. The reason is likely the Iraqi army’s inability to train its troops to use these new vehicles. The United States should be much more heavily engaged in training Iraqi soldiers.

Training has been one of the key areas of focus for the tiny deployment of 3,360 U.S. troops to Iraq, but those troops do not have the resources to teach significant proportions of the available Iraqi soldiers. As of late September, just 11,500 out of a possible 250,000 Iraqi soldiers had undergone the training. Training of Iraqi soldiers and leadership must be at the forefront of efforts to defeat ISIS in Iraq, and in order to do so effectively, the United States must substantially increase the number of special operations and infantry soldiers deployed to Iraq.

A resident gestures as he talks to a U.S. soldier from 2nd Brigade combat team, 82nd Airborne on patrol in Baghdad's Adhamiya district, January 5, 2008. Mahmoud Raouf Mahmoud / Reuters Along with training, the United States must be willing to accept increased risk in a few critical areas. The U.S. Army is already putting “boots on the ground” to support key leader engagements with Sunni tribal leaders. This mission should be expanded to include the integration of U.S. military advisers with Iraqi security forces down to the brigade level, throughout training, mission planning, and execution. Such programs will enable U.S. advisers to develop a full and accurate picture of the current strengths and weaknesses of the individual Iraqi units for follow-on training. They will also ensure that Iraqi military leaders are developing and distributing all aspects of the missions—such as communication, medical evacuation, and reinforcement plans—evenly across all frontline battalions.

If the United States is unwilling to double down on its strategy in Iraq, it risks ceding its role to a bullish Russia, which would only further inflame the conflict. The United States has the right idea in Iraq. Empowering local Sunnis to take a leading role in the fight against ISIS, relegating Shiite militias to the sidelines, being cautious about civilian casualties, training armed forces, and equipping them with counterinsurgency-focused gear are all elements of a winning strategy. But the United States must be prepared to seriously invest in its strategy by substantially increasing the number of troops it has deployed to Iraq and by giving them latitude to build relationships, call in air strikes, and act as a neutral arbiter between Sunnis and Shiites participating in this war. If it does not, Iraq may completely lose confidence in the merits of the U.S. strategy—to the detriment of all.