The Middle East, where the US military is currently deployed in three conflicts, barely got any mention in the two presidential debates between Donald Trump and Joe Biden, but is likely to see a policy pivot if the Democrats win the White House on Tuesday.
Mr Biden, 77, if elected, would bring the longest foreign policy experience for any sitting US president in recent history. Having been a member and then chair of the Senate Foreign Relations Committee for more than two decades, and later in charge of critical foreign policy portfolios as vice president to Barack Obama, Mr Biden is no stranger to international affairs.
In the Middle East, Mr Biden is known for his controversial proposal as senator to divide Iraq among its three major sects in 2006, and for having close relations with regional leaders. But if elected, experts say, the former vice president would bring changes to three critical foreign policy arenas in the Middle East: Iran, Turkey and Syria.
Return to Iran nuclear deal
Mr Biden has made it clear that he would return to the Joint Comprehensive Plan of Action (JCPOA), the 2015 nuclear deal with Iran that the Trump administration withdrew from in 2018. But such return is contingent on Iran’s compliance.
“If Iran returns to strict compliance with the nuclear deal, the United States would rejoin the agreement as a starting point for follow-on negotiations,” Mr Biden wrote in a column published by CNN last month.
Ariane Tabatabai, a Middle East fellow at the Alliance for Securing Democracy at the German Marshall Fund, described an Iran policy under Mr Biden as one that turns the page on Mr Trump’s but does not necessarily return to Mr Obama’s.
"The most significant difference [between Mr Trump and Mr Biden] in my view is one where a potential Biden administration would be in line with the Obama administration, and would seek to rebuild international consensus on Iran and work with US allies," Ms Tabatabai told The National.
Biden and Trumps make last-ditch appeals in crucial state of Florida
But where Mr Biden might differ with the Obama years would be in addressing the regional issues that come with the Iran challenge. “A Biden administration would inherit a much different regional file and frankly, where it begins on that largely depends on what will happen between now and January 20” when the new presidential term begins, she said.
"By the time the JCPOA was reached, it was understood that the regional issues would have to wait for the next administration. Now, as the former vice president has put it, he would be looking to build on the deal by addressing the regional activities too," said Ms Tabatabai, author of No Conquest, No Defeat, a historical overview of the Islamic Republic's national security strategy.
In his column, Mr Biden said he had “no illusions about the challenges the regime in Iran poses to America's security interests, to our friends and partners and to its own people”. But it is not clear whether any US president can force regional issues to the negotiating table with Iran on its nuclear programme. The country is growing more defiant in its nuclear capabilities and has begun construction at its Natanz nuclear facility, according to satellite images.
Bigger rift with Turkey
Another challenge for a Biden presidency would be dealing with a more hostile and hawkish Turkey. In the past six months alone, President Recep Tayip Erdogan’s government has tested the Russian S-400 missile defence system, increased Turkish involvement in the Libyan and Syrian wars, challenged the EU in the East Mediterranean, and involved Ankara in the Nagorno-Karabakh conflict between Armenia and Azerbaijan.
But throughout, Turkey's president has had a warm personal relation with Mr Trump, who called him "a friend", "an ally", and "hell of a leader". According to the New York Times, Mr Erdogan recruited Trump officials to quash a lawsuit in New York against Turkey's Halkbank. The state-owned bank is now charged with embezzlement, conspiracy, money laundering, fraud and helping Iran evade sanctions.
This warm relationship is unlikely to carry on into a Biden presidency, said Aaron Stein, director of research at the Foreign Policy Research Institute.
"I anticipate some tough words for Turkey from a Biden administration," Mr Stein told The National. He said a Biden presidency would start enforcing sanctions on Ankara under CAATSA, the Countering America's Adversaries Through Sanctions Act, for its acquisition of the S-400 system. These are mandated by Congress but Mr Trump has delayed their application for 16 months.
Mr Stein did not foresee a return to the Obama years under Mr Biden. The former US president visited Istanbul during his first 100 days and maintained a good working relationship with Mr Erdogan on issues related to the Arab uprisings, Iraq, and the situation in Gaza.
But Mr Stein saw a tilt away from Turkey for Mr Biden. “He would continue to tilt towards Greece in crisis spots like the East Med, and show even more scepticism about US involvement in Syria.”
The former vice president has had a good rapport with the Kurdish leadership and minority over the years. Turkish officials were furious at Mr Biden for saying in January that he was “very concerned” about Mr Erdogan’s policy toward the Kurds in Turkey.
Calling Mr Erdogan an “autocrat”, the former vice president encouraged support to the Turkish opposition.
"What I think we should be doing is taking a very different approach to him [Erdogan] now, making it clear that we support opposition leadership … to be able to take on and defeat Erdogan. Not by a coup, not by a coup, but by the electoral process," Mr Biden told the New York Times.
Re-engagement in Syria
Another area where Mr Biden could challenge Turkey is Syria, said Charles Lister, a senior fellow at the Middle East Institute.
"A Biden administration would remain engaged in Syria, sustain and potentially re-empower the counter-ISIS mission, protect our local Syrian Democratic Forces (SDF) partners and challenge Turkey more determinedly," he told The National.
At the same time, there would be a shift from the Obama years where the Syrian conflict sprouted into a humanitarian and counterterrorism disaster. “Ultimately, I think many of the folks around the former vice president realise that under Mr Obama, the crisis in Syria was allowed to get out of hand and the effects of that have been profound – most if not all of them costly to US interests,” Mr Lister said. In a primary debate, Mr Biden did not commit to withdrawal US forces from Syria.
On the question of talking to the Assad regime, after Mr Trump sent his adviser Kash Patel to Syria over the summer to discuss the issue of hostages, Mr Lister expected a diplomatic push from Mr Biden but not engagement with Damascus. “The campaign has made it very clear that re-engagement with the regime is off the table, at least not without a UN-backed political process and a meaningful negotiated outcome,” he said.
Mr Biden's regional policy will also hinge on who he appoints to top cabinet posts. Key contenders for the secretary of state job such as former national security adviser Susan Rice, Senator Chris Murphy, Mr Biden’s aide Tony Blinken or former undersecretary of state Bill Burns, see regional priorities differently.
The former vice president is also expected, if elected, to continue Mr Trump’s Arab-Israeli normalisation push, take a tougher stance on human rights in the region, review arms sales to Saudi Arabia, and push harder stance to end the Yemen war.
