No mention of Saudi Arabia in Barack Obama's speech on destroying Islamic State. Credit:Reuters Well yes … and no. A subsequent investigation, the so-called 9/11 Commission, looked into the allegations and, commission director Philip Zelikow told The New Yorker his investigators could not substantiate what he described as "wild accusations that needed to be checked out … an agglomeration of preliminary, unvetted reports". The core allegation in the document reportedly is that two of the hijackers were helped and might have been funded by Saudi diplomats stationed in the US. Lawyers acting for the victim families want the document released, in the belief that it will help their legal action against Saudi Arabia and other defendants. Riyadh is on the record demanding that the document be released, so that it can refute what it casts as a bid to "malign our country and our people". Reflecting the tense complexities of the Washington-Riyadh relationship and perhaps the human rights shortcomings of most of his regional allies, Obama refrained from naming Riyadh and any of the other Sunni capitals in his address to the nation on Wednesday evening.

Saudi involvement? The World Trade Centre in New York after one of two airliners crashed into it on September 11, 2001. Credit:Getty Images Similarly he shied away from any attempt to assign them particular tasks as would-be members of a coalition he has charged with destroying the brutal jihadi Islamic State, which has taken control of swathes of Syria and Iraq. Collectively the Arab countries have enormous military and security apparatuses. But it seems that apart from controlling the flow of fighters and funds to the conflict, the Saudis' only big-ticket commitment is to train fighters for the Free Syrian Army, considered to be a moderate element among the various rebel and insurgent forces fighting in Syria. A coyly worded communique issued after a meeting of representatives of 10 Middle Eastern governments and US Secretary of State John Kerry in the Saudi city of Jeddah on Thursday made no reference to the Saudi training commitment that was leaked by US officials. Mentioning no specifics, the statement called for a coordinated military campaign, with all nations present at the meeting contributing "as appropriate". Likewise, it made only glancing references to what American officials said would be specific requests for the Arab governments to be more vocal in condemning IS and to enlist government-owned media, like Al Jazeera, and their religious leadership to do likewise.

The challenge for Obama is to negotiate conflicting regional agendas and to keep leaders' minds on the immediate task - and not muddy the effort to eliminate IS with local infighting. Riyadh is a classic example in this regard. It is determined to see off Syria's beleaguered dictator, Bashar al-Assad, because of the damage Assad's demise would inflict on Syria's ally, Iran. But IS (also called ISIL) is one of the strongest rebel forces fighting in Syria and it can be argued that any containment or defeat of IS by the Obama coalition, relieves the pressure on Assad. Analysts argue that the leaders of the so-called moderate Sunni states are now fixated on the threat posed to their regimes by IS. But there is no clarity on what they might do militarily as part of a coalition to squeeze IS - thereby helping genuinely to head off the perception that this is another Western war against Muslims. There is also little clarity on how the moderate Sunni states would defend themselves, instead of relying on others to defend them.

When Obama was asked about the role of Iran, in a recent interview with The New York Times, he responded: "I think what the Iranians have done is to finally realise that a maximalist position by the Shia in Iraq is, over the long term, going to fail. And that's, by the way, a broader lesson for every country [in the region]: you want 100 per cent, and the notion that the winner really does take all, all the spoils. "Sooner or later that government's going to break down." Therein, Obama put his finger on a tactical flaw in trying to work with the region's leaders - they all have their own agendas and they all want 100 per cent. He needs them, but he can't rely on any of them.