President Barack Obama and his administration may have found themselves caught in a tangle of mixed messaging, but American power is now clearly directed at ISIL.
Mr Obama maintains that ISIL will be “degraded and destroyed”, two fundamentally different objectives. The White House says the US is at “war” with ISIL in the same way it has been at war with Al Qaeda, while the state department insists there is no “war”.
And there’s unmistakable tension between categorical assurances that ISIL will be defeated and strong commitments to the American public that no major undertaking is underway.
But such quibbles aside, this is indeed a necessary, unavoidable and morally unimpeachable war.
In their own interests, key US Arab allies can and must play central roles to ensure success. Since this is almost equally important to all the relevant parties, the burden should be similarly shared: from each according to their ability and to each according to their need.
Those Arabs dissatisfied with present levels of American commitment need to recognise several key realities.
First, the US is the only major outside player to have taken significant, concrete and direct action against these fanatics.
Second, it’s taking the initiative in building a much-needed international and regional coalition to address this cancerous menace. Third, the US is doing this reluctantly.
Fourth, sustaining and developing this American leadership commitment will depend, in part, on the US government and public believing that it has the appropriate level of regional and Arab support.
Mr Obama has already engaged in, and described to the American public, what amounts to an organically developing campaign.
US air strikes were initially said to be limited to protecting Erbil and relieving stranded Yazidi refugees. Then came the reconquest of the strategically vital Mosul Dam.
Later still, American air strikes supported various local forces combating ISIL in disparate places and for different purposes.
Now, Mr Obama says he’s authorising air strikes in Syria, a contingency virtually ruled out only a matter of a few weeks ago.
Moreover, the Obama administration has been moving quickly to frame the campaign against ISIL for the American public in widely acceptable counterterrorism and “war on terror” terms, and disassociate it from the highly unpopular war in Iraq.
Since ISIL is a direct offshoot of Al Qaeda in Iraq and Mr Obama has previously campaigned heavily in support of a “war” against Al Qaeda, this argument resonates with the American public, who now overwhelmingly support the air campaign.
Some Arabs doubt that such an international coalition is required to defeat ISIL, saying instead that such a broad partnership should target a wide range of violent extremists.
But the battle against ISIL alone will indeed be challenging and complex, particularly dislodging it from its strongholds in Syria, and arranging the ground forces required to defeat them. The CIA now estimates there are more than 30,000 ISIL fighters in Syria and Iraq. This won’t be quite so quick or easy.
To be effective against ISIL, local ground forces cannot be perceived as sectarian, or sectarian-led. Sunni-majority Arab states have an essential role in developing effective anti-ISIL troops, and training and arming them.
They must be credible in the eyes of the deeply aggrieved Sunni populations that ISIL rules and claims to represent. Hassan Hassan, a columnist for this newspaper, describes these forces as a potential "Sunni peshmerga", an equivalent to Kurdish militias that have, at times, successfully combated ISIL.
Arab states should also help shape public opinion so this campaign both isn’t, and isn’t seen as, bolstering sectarian anti-Sunni interests or benefiting the Assad dictatorship in Syria.
The Jeddah Communique of September 11 was a positive development that challenged sectarian divisions. The new Iraqi government, which was recognised as essential, joined the Gulf Cooperation Council, Egypt, Jordan and Lebanon in jointly endorsing the American-led coalition. Saudi Arabia may finally reestablish a Baghdad embassy, amid other signs of a crucial thaw in regional tensions.
Some Arab states will have political, social, intelligence and air power capabilities that can be crucial in creating an effective and broad-based coalition against ISIL.
Other forms of cooperation such as enhanced ground support, fly-over arrangements and various forms of covert activity will also certainly be required, as will cracking down against fund-raising and recruiting. So the key Arab states have indispensable symbolic and practical roles in the struggle to crush ISIL.
But, in order to maintain the American momentum, Arab support must be enthusiastic and concrete and not vague or non-committal. While there are many other American perceptions, the New York Times’ immediate response to the Jeddah Communique was a story with the headline: Arabs Give Tepid Support to US Fight Against ISIS.
The mere presence of such an impression in the American conversation ought to be enough to urgently prompt Arab states and societies to ensure their support for the campaign against ISIL is never again mistaken in Washington as “tepid.”
Hussein Ibish is a senior fellow at the American Task Force on Palestine
On Twitter: @Ibishblog