WASHINGTON - President Joe Biden and Israeli Prime Minister Benjamin Netanyahu finally spoke Friday after a glaring, nearly four-week gap in direct communication during which fundamental differences have come into focus over a possible pathway to Palestinian statehood once the fighting in Gaza ends.

Biden and his top aides have all but smothered Netanyahu with robust support, even in the face of global condemnation over the mounting civilian death toll and humanitarian suffering in Gaza as the Israelis have carried out military operations in the aftermath of the Oct. 7 attack on Israel.

But the leaders’ relationship has increasingly shown signs of strain as Netanyahu has repeatedly rebuffed Biden’s calls for Palestinian sovereignty, gumming up what the U.S. president believes is the key to unlocking a durable peace in the Middle East - the oft-cited, elusive two-state solution.

Neither side shows signs of budging.

Friday’s phone call came one day after Netanyahu said that he has told U.S. officials in plain terms that he will not support a Palestinian state as part of any post-war plan. Biden, for his part, in Friday’s call reaffirmed his commitment to work toward helping the Palestinians move toward statehood.

“As we’re talking about post-conflict Gaza ... you can’t do that without also talking about the aspirations of the Palestinian people and what that needs to look like for them,” said National Security Council spokesman John Kirby.

The leaders spoke frequently in the first weeks of the war. But the regular cadence of calls between Biden and Netanyahu, who have had a hot-and-cold relationship for over three decades, has slowed considerably. Their 30- to 40-minute call on Friday was their first conversation since Dec. 23.

Both sides are hemmed in by domestic political considerations.

The chasm between Biden, a center-left Democrat, and Netanyahu, who leads the most conservative government in Israel’s history, has expanded as pressure mounts on the United States to use its considerable leverage to press Israel to wind down a war that has already killed nearly 25,000 Palestinians.

There is also growing impatience with Netanyahu in Israel over the lack of progress in freeing dozens of hostages still held by Islamic militants in Gaza.

“There is certainly a reason to be concerned,” says Eytan Gilboa, an expert on U.S.-Israeli relations at Israel’s Bar-Ilan University, “The more and more we see political considerations dominating the relationship between Biden and Netanyahu, which is likely to continue because of the upcoming presidential election and the weakness of both leaders, the more we will see them pulling apart.”

In their most recent calls, Biden’s frustration with Netanyahu has grown more evident, even though the U.S. leader has been careful to reaffirm his support for Israel at each step, according to U.S. officials who requested anonymity to discuss the leaders’ private interactions.

Yet, Biden, at least publicly, has not given up on the idea of winning over Netanyahu. Asked by a reporter on Friday if a two-state solution is impossible while Netanyahu is in office, Biden replied, “No, it’s not.”

Aides insist Biden understands the political box Netanyahu finds himself in with his hard-right coalition and as he deals with ongoing corruption charges that have left the prime minister fighting for his freedom, not just his political future.