US President-elect Joe Biden has pledged to make Saudi Arabia a "pariah" over its human rights failings, but observers say the oil-rich Arab powerhouse still holds enough leverage to deflect a major rupture in relations.
Crown Prince Mohammed bin Salman, whose Shakespearean rise to power coincided with the start of Donald Trump's presidency, has largely escaped US censure thanks to his personal ties with the administration.
But Trump's defeat leaves the de facto ruler vulnerable to renewed scrutiny from the kingdom's closest Western ally, which could leave him isolated amid economic challenges that imperil his reform agenda, a griding war in neighbouring Yemen and pockets of opposition to his rule.
While Trump and his son-in-law Jared Kushner -- who struck up a close rapport with the crown prince -- shielded the heir to the Saudi throne, Biden has vowed to reassess the relationship.
He has slammed what he calls Trump's "dangerous blank check" to the kingdom, pledged justice for journalist Jamal Khashoggi's 2018 murder by Saudi agents and vowed to suspend US arms sales over the catastrophic war in Yemen.
Biden has threatened to make Saudi Arabia "the pariah that they are".
Still, observers say, decades-old military and economic relations -- based on cooperation over counter-terrorism and maintaining stability in oil markets -- are unlikely to be upended.
Although the US has reduced its reliance on Saudi oil in recent years, the kingdom remains a key customer for American defence industry giants and military contractors.
And observers say Biden would need to work with Saudi rulers on a host of hot-button issues in the tinderbox region, from countering the regional influence of common foe Iran to fighting a newly resurgent Islamic State group.
"A Biden administration will no doubt take a harder line on human rights than its predecessor, but it is unlikely to completely abandon the Saudi-American partnership," David Rundell, former chief of mission at the US embassy in Riyadh, told AFP.
"While the United States has become more energy independent due to fracking, important American allies like Japan and Korea have not," added Rundell, author of the book "Vision or Mirage, Saudi Arabia at the Crossroads".
- Policy or rhetoric? -
Riyadh appears wary of Biden's pledge to revive a 2015 nuclear pact between world powers and Iran, a controversial deal that was negotiated when he was vice president under Barack Obama.
The landmark agreement was shredded by Trump, who chose to go to Riyadh on his first overseas visit as president in 2017, when Saudi rulers lavished him with gifts, a sword dance and a glowing orb.
To ensure the deal's success this time, analysts say Biden would have to seek consensus among regional states, including Saudi Arabia, which are traditionally opposed to diplomacy with Tehran.
"Nobody expects Biden to travel first to Riyadh and perform a sword dance, but he needs Saudi for any regional buy-in of a new Iran deal, in counterterrorism support, Israel-Palestine, oil market stability," said Saudi author and analyst Ali Shihabi.
Biden has separately expressed support for recent Arab-Israeli normalisation accords with Middle East nations, including Bahrain, which is unlikely to have signed up without a nod from Riyadh.
Observers say Prince Mohammed could use Saudi Arabia's possible future normalisation with Israel -- the biggest diplomatic prize for the Jewish state -- as a negotiating tool.
"Many in Riyadh believe that a normalisation deal with Israel would put Prince Mohammed in a much better position with a Biden administration," Cinzia Bianco, a research fellow at the European Council for International Relations, told AFP.
"Everything depends on how hostile a Biden administration would actually be, in policy, not in rhetoric, towards Saudi Arabia from January onwards."
- 'Make him accountable' -
Saudi observers dismiss Biden's campaign speeches about the kingdom as bluster, pointing out that Trump also struck a hostile note in his 2016 campaign before warming up to its rulers.
Biden's pledge to suspend Saudi arms sales runs contrary to his past record.
When he was vice president, the US offered the kingdom's military not just logistical and intelligence support, but also weapons worth over $115 billion, more than any other previous administration, according to 2016 data from the US-based Security Assistance Monitor.
Even so, relatives of Saudi prisoners of conscience are pinning their hopes on Biden. They expect he will place stronger conditions on US support, such as demanding their unconditional release.
Prince Mohammed has overseen a sweeping crackdown on dissent, with dozens of activists, journalists, clerics and even royal family members detained in recent years.
"We are hoping that (Biden) will make human rights abuses in Saudi Arabia a priority, which has been neglected by the current Trump administration," said Walid Alhathloul, the brother of activist Loujain Alhathloul, who has been jailed for over two years and is currently on hunger strike.
"It's time for the US to restore the international order and to make (Prince Mohammed) accountable," he told AFP.