It took a war in Gaza for Joe Biden to make his first phone call to Abdel Fattah al-Sisi, the president of Egypt.

The US president had snubbed Sisi in his first four months in office, a sign of displeasure over Cairo’s human rights record and a reversal of his predecessor Donald Trump’s policy. “There will be no more blank cheques for Trump’s favourite dictator,” Biden had said while campaigning.

But as the conflict between Israel and Palestinian militants Hamas escalated in recent weeks, the two leaders spoke twice. Cairo’s successful negotiation of a ceasefire in Gaza ending the 11-day war that killed 243 Palestinians and 12 Israelis has underscored its relevance as a mediator in the region’s oldest and most intractable conflict. It also earned it public thanks from Biden.

The account of the call with Biden released by Sisi’s office this week listed the reasons why Cairo should remain an important partner to the US. Biden, according to Cairo, confirmed the US administration looked forward “to strengthening bilateral relations . . . in light of Egypt’s pivotal role regionally and internationally and its effective political efforts to support the region’s security and stability and resolve its crises”.

In a nod to Biden’s presumed concerns about freedoms in Egypt, Washington’s readout said the US president “thanked Egypt for its successful diplomacy” and “underscored the importance of a constructive dialogue on human rights”. Antony Blinken, US secretary of state, met Sisi in Cairo on Wednesday as part of a Middle East tour to bolster the truce. He said that Egypt was a “real and effective partner” that helped end the Gaza war.

Washington’s acknowledgment of Cairo’s importance in halting the violence makes clear the limits of the “historic peace agreement” between the United Arab Emirates and Israel last year. Palestinians saw it as a betrayal even as Abu Dhabi argued the accord would help ease their protracted conflict with Israel.

A wealthy Gulf state, the UAE is a regional powerhouse that has projected influence in places as far as Libya and the Horn of Africa. But when it comes to the Palestinian issue heavily indebted Egypt is still uniquely placed, diplomats and analysts said. The first Arab country to make peace with Israel in 1979, Egypt has diplomatic and security links with the Jewish state going back decades.

“Mediating a crisis requires a credible connection to both sides,” said Kristin Diwan, resident scholar at the Arab Gulf States Institute in Washington. “At least in the short term, the UAE has burned its connections to the Palestinians due to its dealmaking with the Israelis. While Egypt’s influence in the region has waned it still retains political and cultural capital and important ties built through its historic relationships.”

Unlike the UAE, Egypt has not only a long history of mediation in the Israeli-Palestinian conflict but also shares borders and security interests with both Israel and Gaza, the Palestinian territory controlled by Hamas. Under Sisi, Egypt and Israel have deepened intelligence co-ordination to combat the emergence of Isis in the northern parts of the Egyptian Sinai peninsula. The two countries have also enforced a blockade over Gaza since 2007 when Hamas seized control of the territory.

“Israel has four decades of proven peace with Egypt,” said an Arab diplomat. “There is trust which exists between them and they have respect for each other, even if they differ sharply on the issue of the Palestinians. As for Hamas, the relationship with Egypt is played on the level of interests. If Hamas wants Egypt’s collaboration on some issues, like opening border crossings, it too has to collaborate with Egypt.”

Egypt’s intelligence services handled the ceasefire negotiations and have played a similar role to end all previous wars between Hamas and Israel. “I am sure the UAE would have liked to be able to do that to show that there is a peace bonanza,” said the diplomat. “But I think for this they would have needed better relations with the Palestinians.”

Egypt’s control of crossings into Gaza gives it leverage over Hamas. Although the Sisi regime is ferociously anti-Islamist and has declared the Muslim Brotherhood, the group ousted from power in 2013, a terrorist organisation, it has managed to forge a modus vivendi with the Palestinian militant group, an offshoot of the Brotherhood. “Egypt’s policy towards Hamas has been pragmatic,” said Ahmed Kamel al-Beheiri, an analyst at the Al Ahram Centre for Political and Strategic Studies, a Cairo think-tank.

The role played by Cairo in bringing about the ceasefire cannot help but influence Biden’s policy on Egypt, analysts say. Cairo is a major recipient of US military aid, $1.3bn per year, but activists and lawmakers want delivery of this aid to be conditioned on improved human rights.

Under Sisi, who led a popularly backed coup in 2013 that ousted an elected Islamist president, there is little room for dissent and tens of thousands of Islamist and secular regime critics have been imprisoned. International human rights groups regularly lambast Egypt over curbs on freedom of expression, unfair trials and the use of capital punishment.

Michael Wahid Hanna, director of the US programme at the International Crisis Group, a conflict-resolution think-tank, said the latest developments “put into stark relief” the question of how an administration that vowed to place human rights at the centre of US foreign policy should deal with Egypt.

“These events have accelerated a discussion which was somewhat in the background but which eventually Biden would have had to deal with” he said. “The question is how to balance interests with the purported commitment to human rights and democracy. It will be a difficult balancing act.”