What will happen to the Mideast’s most significant peace push in more than a quarter century if America turns its back on Saudi Arabia?

As Riyadh and its Gulf allies break long-held taboos on the multi-generational Arab-Israeli dispute, the poll-leading presidential candidate, Vice President Biden, signals a return to the Obama-era advocacy of “balance” between Gulf Sunnis and Shiite Iran, widely seen in the region as favoring the Islamic Republic.

Marking the second anniversary of a horrific crime committed by Saudi agents, the killing of Washington Post columnist Jamal Khashoggi, Mr. Biden vowed that “Jamal’s death will not be in vain.”

“Under a Biden-Harris administration,” Mr. Biden wrote in a statement, “we will reassess our relationship with the Kingdom, end US support for Saudi Arabia’s war in Yemen, and make sure America does not check its values at the door to sell arms or buy oil.”

The statement was released just as one of Riyadh’s most recognized faces in America, Prince Bandar bin Sultan, in a eye-popping interview, accused the Palestinian leadership, rather than Israel, of hindering peace. He also berated Ramallah for betraying its Arab supporters.

“I think the circumstances and times have changed, and I think it is only fair to the Palestinian people to know some truths that have been kept hidden,” the palace insider told the Dubai-based, Saudi-financed al Arabiya television.

Delivering a history lesson reminiscent of Abba Eban’s “the Palestinians never missed an opportunity to miss an opportunity,” Prince Bandar cited nationalist Haj Amin al Husseini’s pact with Adolf Hitler and Yasser Arafat’s enthusiastic support for Saddam Hussein’s invasion of Kuwait.

And “Who are the allies of the Palestinians now?” he continued, “Is it Iran, which is using the Palestinian cause as a bargaining card at the expense of the Palestinian people? Iran and Khomeini, who want to liberate Jerusalem through Yemen, Lebanon, and Syria?”

Palace watchers say the prince, who no longer holds an official title, nevertheless speaks for the Kingdom. His interview, surely okayed by the de-facto ruler, Crown Prince Mohamed bin Salman, is seen as encouragement for Arab countries to join the United Arab Emirates and Bahrain, which have signed on the White House lawn a pact to fully normalize relations with Israel.

Such a major shift in Mideast politics was mostly ignored on the campaign trail, and the Nobel committee ignored it Friday, awarding the peace prize to the World Food Program. Yet, the cause of peace is advanced when Saudis and their allies push to end enmities that for more than a century plagued the region and the world.

Prince Bandar’s interview is widely seen as a hint that the Saudi leaders themselves are now itching to formalize hush-hush cooperation with Israel. Prodding from Washington is a major factor in the drive to reverse long-held beliefs in a traditional society. America’s sway in Riyadh would surely wane were Washington to turn its back on the Saudis in an effort to coax Iran into renegotiations.

Mr. Biden is yet to detail explicitly a coherent Iran policy. Advisers in his inner circle urge a full return to America’s “balanced” approach of his veep days. Remember? In 2016 President Obama called on the Saudis to end their “competition” with Iran and, instead, “find an effective way to share the neighborhood and institute some sort of cold peace.”

Mr. Biden wants to “reassess” relations with Riyadh and deny American arms until it adopts our “values.” Will he similarly condition Iran negotiations on ending the Islamic Republic’s human rights violations?

Yes, the Democrat contender tweeted about one “travesty” — Tehran’s execution of Olympic wrestler Navid Afkari, who protested against the regime. Would Mr. Biden, though, join a growing chorus calling on the International Olympics Committee to ban Iran from participating in international competition? Would he call to release Afkari’s brothers, Vahid and Habib, still imprisoned and being tortured?

Veterans of the Obama administration denounce President Trump’s Iran policy of “maximum pressure.” Mr. Biden, while threatening to cut support for Riyadh, contemplates a full return to the nuclear deal that Mr. Trump has discarded.

The current president “betrayed our friends and embraced dictators around the world,” Senator Kamala Harris said in the vice presidential debate. Yet Mr. Trump reversed his predecessor’s embrace of Iran at the expense of Saudis and Israelis.

Mr. Trump and his son in law, Jared Kushner, pushed Israel and the Gulf states to formalize ties once considered taboo in the Arab world. Instead of rebalancing the region or favoring dubious Iran deals, Mr. Biden would do best, if elected, to build on that promising trend.

Twitter @bennyavni