The willingness of Arab states to finally sacrifice blood and treasure to defend the region from terrorism and Iranian encroachment is a positive development. But it also represents a growing desperation in the shadow of Washington’s shrinking security role in the Middle East.

After the start of the Saudi-led air campaign in Yemen, United Arab Emirates Minister of State for Foreign Affairs Anwar Gargash described the intervention as “a new page of Arab cooperation for security in the region.” Although the initial progress was promising, it is not clear the enthusiasm will endure—or be effective.

The most important Arab League contribution in Yemen would be a troop deployment. But it is far from clear that Arab states would be willing to sustain casualties. Cairo has indicated that it would send combat troops to Yemen, yet the Egyptian public may be sensitive to fatalities: 50 years ago Egypt lost 26,000 soldiers in an ill-fated military intervention in Yemen. Saudi Arabia deployed troops to fight the Houthis in 2009-10 but withdrew after three months when casualties started to mount.

There are also concerns about the military capabilities of Arab coalition partners. While Sudan, Jordan and Egypt have contributed air assets to the Yemen campaign, these states reportedly cannot fly night sorties. Consider that in the past four months, Arab allies in the U.S.-led anti-ISIS coalition have conducted only about 8% of airstrikes in Syria and Iraq. Already, just days into the campaign, Saudi Arabia and Sudan have reportedly lost aircraft. In the absence of a significant U.S. role, logistics maintenance and interoperability may also pose problems.