The headlines confirm Iraq and Syria remain the current center of gravity in the U.S.-led coalition’s fight against ISIS. Yet, even as the group’s core territory constricts, the coalition still will need to neutralize ISIS combatants wherever they are and halt the spread of their dangerous ideology. American officials designing this larger campaign are looking to Jordan as a key contributor. It is a steadfast and strategically important ally, fully committed to this fight despite the increasing pressure it faces. King Abdullah’s visit to Washington last week was a good start, but more must be done to strengthen cooperation with a critical partner in the joint effort against ISIS.

Jordan is an original coalition member and has paid a high price. In 2014, a Jordanian F-16 pilot flying a mission against ISIS crashed in Syria and was captured by this despicable enemy. The next month they burned him alive and propagated online video of his savage execution. King Abdullah pledged an “earth-shaking” response and vowed to fight ISIS until his country runs “out of fuel and bullets.”

And so he has. Jordan has flown countless airstrikes against ISIS targets in Iraq and Syria. It has opened Prince Hassan Airbase to coalition aircraft and allowed the coalition to operate training bases on its territory. The country also cooperates with Israel and Egypt, two of our other key regional allies. There is no doubting Jordan’s determination – something underscored in our meetings with some of the country’s highest-ranking military officers over the past two and a half years.

The kingdom’s strategic importance is sometimes obscured by the larger, more immediate focus on Raqqa and Mosul, the flow of ISIS fighters through Turkey, and floods of refugees streaming in the opposite direction. Yet these same dynamics are at play along Syria’s border with Jordan.

More than 2,500 Jordanians have gone to Syria and Iraq to fight with ISIS. Compared to Tunisia, Europe and other large sources of ISIS manpower, it is much easier for Jordanians to return home from Syria and Iraq. This makes the kingdom particularly vulnerable to ISIS attacks, especially once Mosul and Raqqa fall and the group’s fighters scatter, or diffuse underground.

Simultaneously, Jordan is targeted by ISIS’s unmatched ability to radicalize susceptible individuals through social media. An estimated 1.4 million Syrian refugees reside in Jordan, perhaps half of them unregistered. Combined with Jordan’s hosting of populations from its other neighbors, fully one in three people in the country is a refugee.

Unfortunately, terrorism is now on the rise. In 2015, two Americans and several Jordanians were killed at a U.S.-run police training program by an ISIS sympathizer. Last year, ISIS attacked the country’s intelligence agency, border guards, and Western civilians.

Left unchecked, this could imperil more than just Jordan. ISIS leaders are looking to reconstitute in new countries as U.S.-led coalition operations pressure them out of Syria and Iraq. Given Jordan’s social and demographic predicaments, ISIS could easily view parts of the country as possible safe havens for planning new attacks. Further ISIS-led radicalization and incitement could spark political unrest that would overwhelm the tiny kingdom and spill across its borders into the West Bank, then Israel.

The United States has taken steps to deepen cooperation with Jordan, but more can and must be done. As the Mosul and Raqqa operations push ISIS south, the United States should augment its roughly 2,300 military personnel assisting the kingdom’s counter-ISIS mission along the Syrian border. There is also room for improved coordination of U.S. and Jordanian operations against ISIS in Syria.

Last year Jordan received $1.26 billion in U.S. aid, thanks to a non-binding Memorandum of Understanding (MoU) now set to expire. This was clearly the right start but should be increased and enshrined in a guaranteed MoU. Additional foreign military financing could help procure and reinforce border security infrastructure, F-16s, combat helicopters and spare parts to keep them operational. Increased Theater Security Cooperation and Security Assistance programs for joint training and exercising will significantly improve multilateral and bilateral capabilities against ISIS.

Non-military cooperation is also vital. The kingdom makes substantial sacrifices, including one-quarter of its annual budget, to accommodate more Syrian refugees per capita than any other country. Last week’s pledge of increased U.S. humanitarian assistance is welcome. Jordan still will need support vetting Syrian refugees in its territory, enhancing its criminal justice system to better fight radicalization, and building infrastructure to access growing energy resources in the Eastern Mediterranean via Israel.

Defeating ISIS requires vanquishing them in Iraq and Syria, but also strengthening other countries where the group seeks a foothold. Jordan is willing and able to play a significant role in realizing these objectives. It is now up to American policymakers to seize the opportunity.