On March 28, 2007, in the dusty city of Fallujah, al Qaeda in Iraq launched a complex attack on the Government Center in the heart of the city, beginning with mortar strikes and machine gun fire to pin down the defenders, followed by two massive truck bombs, one of which was laden with chlorine. As the chemical burned peoples’ lungs, several men wearing suicide vests rushed at the compound only to be cut down by small arms fire from the Marines and Iraqi police.

It was an audacious attack demonstrating the resiliency of an insurgency that had bedeviled American military leaders and their Iraqi allies from shortly after Baghdad fell four years earlier. But al Qaeda in Iraq was already defeated in Fallujah — they just didn’t know it.

Seven months after the attack on the government center, the al Qaeda insurgency was in its death throes. Unable to mount spectacular attacks and faced with a growing and more aggressive Iraqi police and army presence, as well as the tribal awakening movement, al Qaeda’s members fled the area or sought to rejoin Iraqi society by reintegrating with the government. At the end of March that year, there had been roughly 750 security incidents in Fallujah and the surrounding countryside. But by October, thanks to a city-wide pacification campaign plan implemented by the Marines and Iraqi forces, along with efforts by area tribes, there were just over 80. The Government Center attack would prove to be the high point for the insurgency in Fallujah in 2007; no such operation was mounted again that year. Al Qaeda simply couldn’t do it.

As a veteran of Fallujah, having served there with the U.S. Navy as a tribal and political engagement officer for six months in 2007, I often wonder why the great efforts of our country to stabilize Iraq have largely fallen apart. While there are many contributing factors to the collapse of Iraq, there are a few lessons that can be learned from Fallujah’s rejection of al Qaeda in 2007 that may help redeem the mission.

The al Qaeda insurgency in the Fallujah area and, more broadly, Anbar Province had long fed on resentments within the Sunni Arab population at their displacement from the top of Iraq’s political, military, economic, and social hierarchy. The Coalition Provisional Authority had abolished the Iraqi Army, removed the Ba’ath Party and its members from political life, privatized state-owned industries causing massive unemployment, and unsuccessfully protected the Sunni Arab community from Shiite militias. All this drove many Sunni Arabs into the arms of al Qaeda. As the war in Iraq continued and U.S. understanding of Iraqi culture, its politics, and insurgency grew, a new approach was adopted to bring the Sunnis back into Iraqi national life. Many of the policies that had alienated the Sunni Arabs were changed, the U.S. adopted a counter-insurgency approach to fight alongside Iraqis, and the U.S. started to advocate for Sunni interests in Baghdad.

Surge forces exploited a deepening divide between Islamist groups, such as al Qaeda, and nationalist insurgents, who objected to the inclusion of foreign fighters in the resistance and al Qaeda’s brand of virulent Islam. Nationalistic Sunni groups eventually emerged as local partners the U.S. could work with, with the U.S.serving the role as coordinator and facilitator between these groups and Iraq’s army, police forces and central government. U.S. commanders also gained a greater understanding of the importance of Iraq’s tribes to bringing stability to Anbar Province as local communities enlisted in their own defense against the insurgents.

But after the last U.S. troops departed Iraq at the end of 2011, the government of Prime Minister Nouri al Malaki began a deliberate process to marginalize Sunni Arabs from political life. He demobilized local protective forces, adopted overtly sectarian policies, and prosecuted Sunni Arab politicians for allegedly colluding with terrorist forces. Once al Qaeda in Iraq had reconstituted itself in Syria, the collapse of the Sunni Arab heartland to its forces was only a matter of time. The challenge now, as the U.S. recalibrates its policies toward Iraq, is determining what can be done to provide the enduring stability Iraqis crave while ensuring that the sacrifices of our U.S. military and civilian personnel were not in vain.

One of the central reasons Fallujah and Anbar Province turned against al Qaeda was that the broader Sunni Arab community had been offered a set of political concessions and reforms to ensure its role in both Iraq’s central government and its security forces. To retake the territories controlled by ISIS, the Sunni Arab community will need a political rationale to undertake the expensive, risky, and costly strategy of fighting the Islamist movement. However, the political environment in Baghdad is so toxic that, at this stage, neither conciliatory gestures from Maliki nor his removal from office will be sufficient. There is a complete lack of trust and it must be rebuilt. A reform of Iraq’s government must be pursued to institutionalize Sunni Arab interests in a multi-ethnic and multi-religious Iraq.

One approach to consider is a National Dialogue Conference, similar to one adopted by Yemen during the Arab Spring, which has lead to a redrafting of its constitution. A significant political gesture such as this, among many other such moves, would help provide Sunni Arabs a political rationale to turn against ISIS.

As for what the United States can do to help, throughout Fallujah’s awakening and during the broader surge of U.S. forces, the U.S. played a central role in cajoling Iraqi leaders, pressuring them when required, and acting unilaterally when necessary. While President Obama’s decision to send advisers to Iraq is a useful first step to reestablishing U.S. influence there, a more robust effort must be undertaken to both reform Iraq’s security forces and to reach out to disaffected Sunni Arabs looking to partner with the central government.

Even though the Obama administration assigned a senior U.S. military official to help Iraq in June, he must be provided with sufficient resources to enable the U.S. to exercise the consistent and effective influence he must possess to coordinate an enlightened Iraqi military offensive against ISIS. To this end, a robust Special Operations Forces presence beyond simply a modest advisory effort should be sent to Iraq.

As we learned in Fallujah, beating an insurgency like the Islamic State of Iraq and al-Sham requires the combined efforts of Iraqi army, police, and tribal forces. Any single component is insufficient. While the army has the firepower, it lacks local knowledge and the will to fight. Police have the local knowledge but lack the army’s punch. And the tribes have the manpower and the will to fight, but they lack weapons to confront ISIS. Thus, any Iraqi army offensive in the Sunni Arab heartland is unlikely to succeed without local partners.

Along these lines, the U.S. must exert significant political pressure on Iraq’s Government to both remove Maliki from office and to initiate a serious reform of Iraq’s governing structures. However effective the current U.S. ambassador to Iraq may be, it would be useful to bring new leadership to the U.S. Embassy in Baghdad, such as an envoy to reach beyond Iraq for possible solutions, to both reassure Sunni Arabs that the U.S. is serious about bringing stability to Iraq and to chart a new course for U.S. efforts there.

As the black banner of Islamist forces rises over Iraq’s Sunni heartland, U.S. policymakers must avoid the false hope that military solutions alone will solve Iraq’s crisis. As was learned in Fallujah during the Anbar Awakening movement in 2007, any effort to secure the loyalty of Sunni Arabs to the Iraqi Government requires more than force of arms, it requires a coordinated effort to enlist communities in their own defense in a spirit of partnership, empowering them through political reform, and moving past old grievances to chart a new way forward.

Iraq’s Sunni Arabs will eventually tire of the harsh sharia rule imposed upon them by the Islamic State of Iraq and al-Sham, but they will need reassurances that they won’t be betrayed again by Baghdad if the U.S. and Iraq’s Government hope to reestablish a unified country.

Dr. Daniel R. Green is a Defense Fellow at The Washington Institute for Near East Policy and co-author with William F. Mullen III of Fallujah Redux: The Anbar Awakening and the Struggle with al Qaeda which will be published by the Naval Institute Press in September 2014. He is a military veteran of Iraq and Afghanistan. He can be reached at dgreen@washingtoninstitute.org.