The billions of dollars in trade that take place between the United States and Saudi Arabia each year mainly depend on military deals and give rise to the jobs and economic advantages to the United States that are very important for US President Donald Trump.

This has meant that the horrifying story of the death of Saudi journalist Jamal Khashoggi, who settled permanently in the US last year, at the Saudi Consulate in Istanbul has been particularly difficult for Trump, who said the arm deals with Saudi Arabia were too important to cancel though there may be other ways of taking action against his Saudi ally.

Perhaps even more important than profits from the arms trade for the US president is the Saudi partnership with the US in the fight against terrorism and radical Islamist groups such as Al-Qaeda, as well as countering the regional influence of Iran.

It would be possible for the US to cancel the arms it sells to Saudi Arabia, but if it did so the Saudis would possibly withdraw their security collaboration with the US in the fight against terrorism and countering Iran.

The importance of the Islamic Republic of Iran for Trump lies in his frequently stated insistence that its behaviour must change, this being seen as one of the most important tasks of Trump’s foreign policy along with dealing with North Korea.

Without the partnership of Saudi Arabia, a leading Arab Muslim nation in the Middle East region with vast reserves of oil and money, controlling Iran or causing the regime in Tehran serious difficulties would likely be impossible.

Any shift by Saudi Arabia towards changing its relations with Tehran or pursuing business opportunities with China and Russia would threaten Trump’s Middle Eastern policies.

Ahead of the mid-term Congressional elections in the US in November and the president’s desperate need for cheaper oil to satisfy the voters, both Trump and the US Republican Party need Saudi Arabia to win the elections in the US.

Trump’s fate will be determined by the outcome of the Congressional elections, since if the Republicans lose their majority in the House, the president’s impeachment becomes very possible when special counsel Robert Mueller completes his investigation into Trump’s possible campaign ties with Russia.

If the Democrats win the elections, the chances of Trump getting the nomination of the Republican Party in the next presidential elections are also reduced.

With so much invested in deterring radical groups and building intelligence exchanges with Saudi Arabia, sour relations with the country’s rulers could jeopardise US national security in the region and in the United States.

This explains why politicians in Tehran will have welcomed the recent rift between Saudi and American lawmakers, even though Iranian officials have not expressed themselves publicly about Khashoggi’s murder so as not to anger the Saudis.

Their keeping quiet and not using the event as a tool of propaganda against Saudi Arabia has surprised many observers.

It may be that Iranian President Hassan Rouhani is waiting to hear if the Saudis’ disappointment with the US could help Iran ahead of Trump’s new round of sanctions on Iranian oil exports.

Already some clients have reduced their oil purchases from Iran, but received a sanctions wavier from the US, which means that Iran’s oil exports will not reach zero as Trump had previously said they would.

If Saudi Arabia refuses to fill the gap created by the withdrawal of Iranian oil from the market, the price of oil could increase ahead of the winter season, something that would not favour the US or any other Western nation.

Oil plays an important role in regard to policy-making, and Saudi Arabia and Iran’s cooperation on its price, if that happened, would be a major threat for importers.

At Tuesday’s Investment Summit in Riyadh, which has gone ahead despite the withdrawal of some big names as a result of the way the Khashoggi case was handled, the CEO of the French oil company Total said “you see what partnership means during difficult times,” referring to his presence in Saudi Arabia and the company’s withdrawal from Iran.

There has also been talk of Russia filling the gap left by the West’s abandoning Saudi investment projects. Russia announced a project on a supersonic jet with Saudi Arabia just after UK billionaire Richard Branson withdraw from the conference in Riyadh, adding that it was investing $1 billion jointly in Saudi Arabia.

Trump will face hard choices in the way he decides to sanction Saudi Arabia as a result of public pressure, if he is not to provide opportunities for Iran, Russia and China to fill the vacuum.

The coming months may see further surprises, along with a political reshaping of the region.

* A version of this article appears in print in the 25 October, 2018 edition of Al-Ahram Weekly under the headline: The Iranian factor