The Saudis might have good reason to believe they are on their way to becoming one of Roberts' congressionally-designated "losers". US President Barack Obama with Saudi Foreign Minister Adel al-Jubeir in Riyadh. Credit:AP Saudi Arabia has always seemed to be utterly protected from allegations about its role in the 9/11 attacks, as much by a 1976 US law that granted foreign governments immunity as by the historical coziness of Riyadh's relationship with Washington. But there are signs that the White House might soon succumb to pressure to release a highly classified 28-page excerpt of the 858-page Joint Inquiry into Intelligence Community Activities Before and After the Terrorist Attacks of September 2001, which has been suppressed, to save Riyadh – and Washington – from embarrassment over possible Saudi ties to the attacks that go beyond the fact that 15 of the 19 hijackers were Saudi citizens. These developments come on the back of a sizeable body of law, dubbed "lawfare", that has evolved in the US since about 2000, by which parties that have helped designated terror groups, no matter how tangentially - banks, auditors, charities and the like - can be held to be liable for the actions of the group.

At work in all this was the agile mind of lawyer Nathan Lewin, who in reading a little-used 1992 law which allowed actions against terrorists who had attacked Americans abroad, concluded that it had not been fully understood – rather than being confined to suing the actual gunman or bomber in an attack, Lewin argued that any individual or group that had aided in any way a terror group that had killed an American abroad could be held responsible. Smoke rises from the twin towers of the World Trade Centre on September 11, 2001. Credit:AP Such is the congressional support, both senior and bipartisan, for the bid to make Saudi interests accountable for 9/11, that the White House has unleashed a ferocious lobbying effort to thwart it - issuing the thinly veiled threat of a presidential veto should the bill land on Barack Obama's desk. Saudi Foreign Minister Adel al-Jubeir swooped into Washington in March to warn individual members of Congress of Riyadh's proposed economic assault on the US should the bill become law. In the aftermath of the 9/11 attacks, a government victims' compensation fund paid about $US6 billion to 2880 families of the dead and more than $US1 billion to the injured. But the families of more than 40 victims opted to take legal action against various parties, including Saudi Arabia, instead of accepting the government's payouts. Tea is delivered to the Gulf Cooperation Council Summit in Riyadh. Credit:AP

Almost half of the Senate - 46 members - signed a letter of demand to then president George W. Bush for the release of the suppressed 28 pages on the Saudi links to the 9/11 attacks. At the time, New York Democratic senator Charles Schumer said: "Keeping this material classified only strengthens the theory that some in the US government are hell bent on covering up for the Saudis." Barack Obama arrives on Air Force One at King Khalid International Airport in Riyadh. King Salman was not on hand to greet him. Credit:AP The 9/11 Commission report said of the Saudis and 9/11: "We have found no evidence that the Saudi Government as an institution or senior Saudi officials individually funded the [al-Qaeda] organisation." As one commentator observed this week, that's a narrowly tailored sentence.

Awkward: Barack Obama with Saudi King Salman bin Abdulaziz and Bahrain's King Hamad bin Isa al-Khalifa (far right) and Oman's deputy prime minister in Riyadh. Credit:AP According to people who have read them, the 28 pages set out links between the hijackers and a Saudi network that helped some of them when they arrived in California. In particular, it has been alleged that two senior Saudi princes had been making payments to Osama bin Laden since a 1995 bombing in Riyadh, in which five American military advisers died. In a 2002 piece in The Wall Street Journal, Simon Henderson - an analyst for pro-Israel think tank the Washington Institute for Near East Policy - wrote: "US and British officials [told] me the names of the two senior princes. They were using Saudi official money - not their own - to pay off Bin Laden to cause trouble elsewhere but not in the kingdom. The amounts involved were 'hundreds of millions of dollars' and it continued after September 11." Saudi Arabia's former intelligence chief Prince Turki al-Faisal, left, with then Australian foreign minister Kevin Rudd at the Manama Dialogue in Bahrain in December 2010. Credit:AP When I interviewed former Saudi intelligence chief Prince Turki al-Faisal in Riyadh in 2002, he denied that bin Laden was in the service of Saudi intelligence, but pressed on who did deal with al-Qaeda's leader, he told me: "Our intelligence and other departments had nothing to do with him - he had access to [high] officials because of his family's standing in the kingdom."

This week, The Atlantic reported that the 28 pages were said to shed light on Saudi involvement – possibly "by lower-level Saudi officials, or by elements of the government, but not the government 'as an institution'.'' Despite billions in arms sales from Washington to Riyadh, the sun appears to be setting on what was once a pivotal relationship. Credit:AP And alluding to the 28 pages this week, Obama's senior adviser Ben Rhodes told CNN's David Axelrod that "there were a number of very wealthy individuals in Saudi Arabia who would contribute, sometimes directly, to extremist groups, sometimes to charities that kind of, ended up being ways to launder money to these groups. So a lot of the funding … the seed money if you will, for what became al-Qaeda, came out of Saudi Arabia." Realpolitik still underpins the US-Saudi relationship, but a particular problem has been Obama's inability to abide by the sage advice of Riyadh's legendary ambassador to Washington, Prince Bandar bin Sultan: "Make your words soft and sweet – you never know when you have to eat them." As Obama reportedly said of the Saudi relationship in conversation with Prime Minister Malcolm Turnbull, "it's complicated". Even before Obama was elected, at a rally in 2002, he referred to the Saudis as "our so- called allies". In recent weeks, he dismissed the Saudis and other Arab Gulf monarchies as "free riders" with no "skin in the game". He complains that Saudi policies fuel anti-US terror and contribute to chaos in the region.

Obama has doubly infuriated Riyadh – one, by concluding the nuclear deal with Iran; and, two, by acknowledging Iran as a legitimate regional broker, in arguing that Tehran and Riyadh should "share" the region. As Saudis see things, Obama betrayed them by pulling the mat from under Egyptian dictator Hosni Mubarak in 2011; and again, by allowing Syrian dictator Bashar al-Assad to survive – if only for the time being. On the other hand, as much as the Saudis offend democratic and human rights sensibilities and despite the soaring rhetoric of Obama's 2009 speech in Cairo, the President subscribes to the realist school of foreign policy that says Washington and Riyadh need each other. Under Obama, the US has sold Riyadh weapons worth almost $US100 billion, more than any of his predecessors; and despite increasing US energy self-sufficiency, he knows that dozens of allied economies depend on Riyadh's control of world oil prices. Importantly too, Riyadh still depends on Washington for security. As the Saudis are demonstrating in the Yemen war, they couldn't fight their way out of a wet paper bag; they're apparently useful in sharing intelligence, but skittish and self-serving in their handling of conflict and tension in the Middle East; and they are not giving Obama what the US wants in the war on the so-called Islamic State. The bid for a special law to end Saudi immunity in US courts burst into the news in the last days of the New York presidential primaries – and the competing candidates fell over themselves to endorse it. In Congress, the Justice Against Sponsors of Terrorism Act has the backing of 12 Republicans and 10 Democrats - almost double the support it had last year.

On arriving in Riyadh on Wednesday, Obama was snubbed. The 80-year-old King Salman had been happy to travel to the airport earlier that day to welcome Gulf leaders, but he was pointedly absent as Obama alighted from Air Force One. As Obama runs out the clock on his presidency, the Saudis are talking tough – whether or not they can continue to do so remains to be seen. Regional experts resorted to marriage as a metaphor. "Despite all the differences, Saudi Arabia and America are not getting divorced – we need each other," former White House adviser and CIA analyst Bruce Riedel said. It was an "estrangement", not a rupture, according to Fawaz Gerges of the London School of Economics; and a report in Foreign Policy was headlined "The Long Divorce". Economists say a Saudi retreat from the US would hurt the kingdom significantly more than it would the republic. But it's possible too that the threat is a bid for cover for a strategy already in place - according to the Saudi Arabian Monetary Authority, there has been a sharp falling-off in Riyadh's foreign security holdings, from $US533 billion at the end of 2014, to $US395 billion in February 2016. The Saudi star is waning in the US - despite the princes' retention of what The Washington Post describes as a "vast" network of PR and lobbying firms in the US. But in America there are few hot-button issues like 9/11 and there are few lobbies with more power than the families bereaved in that atrocity.

Former US senator Bob Graham put it bluntly: "They are so fearful of what would emerge if there was to be a full trial … the Saudis know what they did; we know what they did."