Contrary to Donald Trump's impulsive policies in the Middle East, Joe Biden is expected to shift back to a more conventional US stance and re-engage with Iran, redrawing regional geopolitics.
In his term in power, Trump's unconventional strategy produced a head-spinning sequence of signature achievements, risky moves and failed initiatives that have transformed the Middle East's political landscape.
The U.S. withdrew from the 2015 nuclear deal with Iran and assassinated its once-untouchable general Qasem Soleimani.
It also moved the U.S. embassy to Jerusalem, breaking with international consensus, and wound back America's military presence in a region Trump believed has lost much of its strategic importance.
But with the election of Biden, the energy-rich region is on the verge of another major shift that could see a tougher U.S. stance on human rights and arms deals.
"This is a region where a... Biden administration is expected to both refocus U.S. policy on issues such as Iran and push for respect of normative values across the region," the European Council on Foreign Relations (ECFR) said in a report.
"Biden has made clear he intends to re-enter the JCPOA (Joint Comprehensive Plan of Action) if Iran also comes back into full compliance and to pursue diplomacy with Tehran on wider issues."
Trump's personalised relationships with regional regimes led to a freeing of the hands of Arab leaders and monarchies, notably Saudi Arabia's young de facto ruler, Crown Prince Mohammed bin Salman.
The businessman-turned-president's warm ties, especially in the Gulf region, contrasted with those of his predecessor Barack Obama, whose deal-making with Iran appalled arch-rival Saudi Arabia and its neighbours.
In a regional game-changer, the U.S. agreed just days ago to sell more than $10 billion worth of top-of-the-line F-35 fighter jets to the United Arab Emirates, to reward its diplomatic recognition of Israel.
Trump's policies generally played well in the Gulf and beyond, especially in Saudi Arabia, despite a lack of action on major incidents like the unprecedented attacks last year against energy giant Aramco, blamed on Iran.
"Saudi officials favoured a second Trump presidency," said Elham Fakhro, International Crisis Group's Senior Analyst for Gulf States.
"They view Trump as having acted to protect their most important regional interests, by imposing a maximum pressure campaign of sanctions against Iran... and by pushing through arms sales to the kingdom."
Now they worry "that a Biden administration will abandon these core interests, by rolling back sanctions against Iran, returning to the JCPOA, and limiting arms sales."
The White House has also pushed back against anti-Saudi resolutions in Congress over its controversial involvement in the Yemen war, which has come at the cost of thousands of civilian lives, and the grisly 2018 assassination of a Saudi journalist in Turkey
"Given the erratic leadership of Saudi Crown Prince Mohammed bin Salman, from his alleged role in the murder of journalist Jamal Khashoggi to his disastrous war in Yemen, MBS could find himself marginalised as Washington takes stock of the pros and cons of its relationship with Riyadh," said the U.S.-based Soufan Centre.
A few hours after the election was finally called, Arab leaders rushed to congratulate Biden. Among the six Gulf countries, only Saudi has not yet reacted.
Biden's regional strategy will have to grapple with a series of thorny issues where Trump is accused of either neglect or mismanagement, from taking a decisive role in ending the war in Libya, to containing a rising Turkey and facing the threat of attacks in Iraq.
Analysts say that one of the administration's first moves will be to restore contact with the Palestinians, who are angered over the Jerusalem embassy issue and also by the U.S. push for the Arab world to normalize ties with Israel.
Biden heartily endorsed the decision by several Arab nations to forge ties with Israel, and he is very unlikely to shutter the new embassy.
However, he is expected to "row back the most negative consequences of the Trump era" with a renewal of U.S. aid to the Palestinians, reopening the Palestinian mission in Washington, and returning to the traditional two-state position, the EFCR said.
"Still, there is unlikely to be a full return to the status quo."