When King Salman of Saudi Arabia visited Moscow last week, even the most sober Russian publications could not refrain from calling the event "epoch-making". Indeed it has taken ten years for a Saudi monarch to return the favour of Vladimir Putin's visit to Riyadh, though, of course, contacts at lower level have been intensifying.
During the visit 14 agreements were signed including understandings on the delivery of some of the crown jewels of the Russian arms industry, ranging from the S-400 air defence system, recently sold to Turkey, to the local manufacture of the Kalashnikov assault rifle.
The announcement of such deals gives substance to high-level visits which otherwise might seem no more than smiles and fine words. There is some scepticism that all these understandings will turn into concrete deliveries, but this has not allayed anxiety in Washington that its long-term ally is discussing defence deals with Russia at a time when its relations with Moscow are the lowest level since the Cold War.
Responding to reports of the S-400 deal with Saudi Arabia, the Pentagon noted that compatibility with existing US-made weapons systems was necessary "to repel common threats". Washington then announced it was ready to sell Saudi Arabia the $15 billion Thaad anti-missile system, as a response to Iran's development of ballistic missiles.
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The visit is the clearest evidence of a new stage in Saudi Arabia expanding its range of partners away from reliance on the United States. The background is clear: concerns about the reliability of its American ally, the disastrous consequences of the Anglo-American invasion of Iraq in 2003, and undisguised exasperation at Barack Obama's courting of Iran. But that still does not answer the question of how the new line-up in the Middle East is going to work.
The American imperium in the region is fraying, but clearly not about to disappear, so it makes sense for a country with an active foreign and security policy to hedge its bets and raise the level of engagement with Russia, which sees itself as a rising power. In the past, disagreements over the regional role of Iran and the fact of backing different sides in the Syrian war have held back the relationship.
In the view of Russian analysts, Saudi Arabia has accepted that Bashar Al Assad has for now retained his position with the support of Moscow and Tehran. The Saudi interest is to prevent Syria becoming an outpost of Iranian power projection, and that cannot be achieved by shouting on the sidelines. Moscow holds the key to limiting Iranian influence, though Mr Putin is unlikely admit to any concerns about his alliance with Iran.
The Russian interest is more of a focus on Syrian reconstruction. Moscow is never going to be able to afford to rebuild Syria – indeed the latest budget proposals suggest stagnation and declining living standards at home after Mr Putin's presumed re-election in March. The Gulf countries are the obvious source for capital.
Taking a broader look, these transactional relationships should now be seen as the norm in the region, in place of fixed alliances. Russia and Saudi Arabia are competitors in the global oil market, yet at the moment they are allied in attempts to prop up the price. Riyadh and Washington are allies, yet the US shale oil industry is the biggest threat to Saudi plans for economic development.
The contradictions in old alliances are most clear with Turkey. Less than a decade ago Washington predicted a "model partnership" with Turkey. Today the two countries cannot even be civil to each other. While Turkey views the Kurdish populations in Iraq and Syria as the greatest threat to its security, the US has chosen Kurdish-led militias as the strike force against ISIL in Syria.
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Not surprisingly, Russia and Turkey have much to discuss. And there is even more, now that Russia has become the major investor in Iraqi Kurdistan, with Rosneft, majority owned by the Russian government, planning to finance the autonomous region's gas pipeline infrastructure.
These investments are not welcomed by the Baghdad government, but they serve two purposes: to raise Russia’s profile as a player in the region and to reinforce its position as a leading global gas exporter.
It is clear that the gradual weakening grip of the US has opened up many new avenues of partnership and discord in the region. What the Russians want to know is whether the Saudis are now willing to work with them, or is their goal simply to weaken the Moscow-Tehran axis?
In an interview with the newspaper Kommersant published in September last year, Sergey Chemezov, head of Rostec and a pillar of the Russian arms export industry, was asked about the progress of arms supply talks with Saudi Arabia. "All our negotiations have not led to any results. In general, for them the negotiating process is a way to exert pressure on our decisions on deliveries of the S-300 [an earlier version of the S-400] to Iran. But this has no effect."
This unusually forthright response reveals the rarely expressed views of an insider. But a year is a long time in Middle Eastern politics, and the Russians will be looking for signs that the changes in Saudi Arabia will allow relations to progress on a broader front, and not be focused solely on containing Iran.
All the signs suggest that Russia is looking for stability abroad and not seeking further military adventures. The Syrian intervention is not in itself popular, with most of the population remembering the Afghanistan catastrophe of the 1980s, but casualties have been so low and control of the media so adept that it is not a political issue.
With uncertainty clouding perceptions of how much Washington can be relied on, Russia feels it does not have to strive to make diplomatic progress, but can wait and see what other countries will bring to it.