There were many unprecedented moments during the two-day Saudi-US summit in Riyadh in May.

The US president joining an Arabian sword dance was one. His wife and daughter attending with their hair uncovered was another.

President Trump delivered a speech to leaders of Muslim nations the next day. This is something no one would have predicted in December 2015, when candidate Trump called for a ban on Muslim visitors to the US.

There was much justified talk about the length and depth of the partnership between the US and Saudi Arabia. It is obvious the kingdom is delighted the previous US president Barack Obama has been replaced by a Republican who agrees with Riyadh about energy and Iran.

But money is at the heart of the new partnership between Washington and the Middle East’s most influential nation. What mattered most was $380bn-worth of deals signed or announced involving trade and investment going in both directions. These included contracts worth $110bn for defence equipment and services. It is the biggest arms order ever signed.

Business has always been key to the US’ relationship with the kingdom, which started in 1932 with the award of Saudi Arabia’s first oil concession to Socal, now known as Chevron. But the contracts announced this month are unparalleled. Critics will say US foreign policy is for sale to the highest bidder under Trump, the billionaire dealmaker.

The differences between the world’s most powerful liberal democracy and its most resiliently conservative autocracy remain enormous. This became clear in the second phase of Trump’s Middle East visit, when he embraced Israel’s Prime Minister Benjamin Netanyahu despite his refusal to countenance concessions acceptable to Palestinian leaders.

Peace talks nevertheless may resume and the US embassy will not be moved to Jerusalem. The kingdom’s demand for a sovereign Palestinian state based on the borders that existed before the 1967 Arab-Israel war will remain unfulfilled. And without real progress in that direction, suggestions that Saudi Arabia will openly engage with the Jewish state in serious ways will remain fanciful.

Even on Iran, Washington is keeping its options open. In Riyadh on 20 May, US secretary of state Rex Tillerson said he was prepared to talk to his Iranian counterpart. The re-election of Iran’s President Hassan Rouhani is something the US cannot ignore whatever the kingdom says.

But at least Trump is listening to Riyadh and will continue to do so as long as the money keeps flowing. And it will.