As war raged in Gaza for the past month, Palestinian Authority President Mahmoud Abbas was a mere bystander.

Routed from the coastal territory by Hamas seven years ago, the relatively moderate Abbas has been confined ever since to the hills of the West Bank, unable to even visit a place that he claims as one half of a future Palestinian state.

But thanks to an unusual confluence of events, Abbas and his government are preparing their return to Gaza — a move that could alter the trajectory of the Israeli-Palestinian conflict by removing a critical barrier to peace.

The return, to manage Gaza’s borders and to oversee a desperately needed reconstruction effort after four weeks of ceaseless Israeli bombing, would accomplish goals that Washington has sought in its endless mediation efforts, but that were out of reach until now.

“Sometimes out of blood, crisis and catastrophe comes opportunity,” said Husam Zomlot, a top foreign policy adviser in Abbas’s Fatah Party. “This hits all the birds with one stone. It ends the division of the Palestinians. It’s empowering the Palestinian Authority. And it’s helping to end the suffering of the people of Gaza.”

It could also force Israel to engage with the Palestinian Authority in a way that it has not had to do in years.

Israeli Prime Minister Benjamin Netanyahu has only grudgingly accepted the idea of a Palestinian state, and has long argued that a peace agreement with Abbas’s government would mean little as long as Gaza remains beyond his grasp. Unlike Fatah, Hamas, an Islamist group that is considered a terrorist organization by the United States, does not recognize Israel.

But Netanyahu is now under heavy pressure both at home and abroad to alter a dynamic that has led to three wars in six years, and has brought Gaza to the brink of collapse.

Asked about prospects for movement toward a two-state solution, the prime minister told foreign journalists Wednesday night that there may be “opportunities that we have not seen before, with a realignment of important parties in the Middle East, to be able to fashion a new reality.”

Of course, no one is betting on a peace deal any time soon, with myriad obstacles still in the way. Even the Palestinian Authority’s return to Gaza in the limited role of manning borders and overseeing reconstruction remains subject to delicate negotiations that continued in Cairo on Thursday.

The host of those talks, the Egyptian government, is pushing hard for Abbas to take control of the Gaza side of the Rafah crossing, along the border with Egypt. Netanyahu, meanwhile, has suggested a willingness to let Abbas run the Gaza side of the crossings into Israel. In recent years, crossings with both Israel and Egypt have been tightly restricted — and often closed. Ending the effective siege of the strip has been a major Hamas demand.

Having Abbas back in Gaza could also make it easier for foreign donors to open their checkbooks, enabling the sort of massive reconstruction effort that Hamas needs in order to show the territory’s 1.8 million people that their suffering during the war was not in vain.

Satellite images released by the United Nations show the impact of Israeli strikes on structures in Gaza. One of the most ravaged areas is the Shijaiyah neighborhood in the southeastern part of Gaza City.

“We are trying to have everyone come in and help run Gaza,” said Ashraf Abu Zayed, a Hamas official. “That will happen only if there is coordination between Hamas and Fatah and the other Palestinian factions.”

But Israel is asking for more than just a change of command at the border crossings. Netanyahu has also demanded Gaza’s demilitarization.

“In my mind the equation is very simple,” said Yitzhak Levanon, a former Israeli ambassador to Egypt. “We need to be generous and lift this siege and open the passages. And the Hamas military wing must be disarmed, so there won’t be any attacks on Israel and Gaza can prosper.”

Hamas has already said that that’s a non-starter. Despite Israeli and international calls for the territory to be demilitarized, Hamas has been adamant that it will not allow anyone to dismantle its armed wing, which is believed to still include thousands of fighters despite the loss, by Israel’s count, of 900 militants during the war.

Hamas has grown stronger

Hamas may have been weakened militarily, but in other important ways, the group has grown stronger since the war, while the Palestinian Authority has withered. Despite a bruising 29-day Israeli campaign that badly depleted Hamas’s weapons stockpile, the group was able to keep firing its rockets to the end. For Palestinians weary of Abbas’s failed negotiations with Israel, the group’s resilience made an impression.

“Hamas’s popularity among Palestinians has dramatically increased,” said Hani Al Masri, director general of the Palestinian Center for Policy Research and Strategic Studies. “Hamas was in a very bad, critical situation. But they proved they were ready for war. They brought the idea of armed resistance back to the Palestinian people.”

That reputation will help Hamas ensure that whoever is running the day-to-day functions of government in Gaza, it remains the territory’s real power.

So, too, will the memory of Fatah’s unceremonious exit from Gaza seven years ago. Hamas had won 2006 Palestinian parliamentary elections, giving it the right to form a government. But the United States, Europe and Israel all cut off funding to the Palestinian Authority as a result, driving a wedge between Fatah and Hamas that led to a 2007 battle on the streets of Gaza that Fatah lost, badly.

In the West Bank, the Palestinian Authority worked with Israeli forces to bring militant groups to heel following the Second Intifada of the early 2000s. But that is unlikely to be repeated in Gaza, with Hamas expected to maintain its armed wing as well as control of internal security.

“There is no question about Hamas policing or controlling the streets of Gaza,” said Mkhaimar Abusada, a political science professor at Gaza’s Al-Azhar University.

Nonetheless, Hamas has appeared willing to allow its old rivals back into the strip under certain conditions. Even before the war, the group had agreed with Fatah and the other Palestinian factions on the terms for a unity government, led by Abbas, that would run the basic institutions of life in Gaza, including schools and hospitals.

The deal was seen as a mark of desperation for the group, which after years of international isolation was so strapped for cash this summer that it was unable to pay its 44,000 civil servants. Since then, Zomlot said, Hamas’s need for help in running the basic functions of government has only grown.

“The powder keg of Gaza is about to explode,” said Zomlot, who was born in a Gaza refugee camp but who, like Abbas, works out of the Palestinian Authority’s administrative capital, the West Bank city of Ramallah. “Hamas knows they can’t handle it.”

And that means, he said, that Abbas, known by his nickname Abu Mazen, will be able to return to Gaza to take on the enormous task of rebuilding, with all the promise and peril that comes with it.

“I don’t think this is a fantasy.” Zomlot said. “Abu Mazen still has a beautiful house in Gaza, and Hamas has so far kept it as is. It’s a matter of when he gets back there, not if.”

Raghavan reported from Gaza City. Sufian Taha in Ramallah and Orly Halpern in Jerusalem contributed to this report.

Correction: An earlier version of this article incorrectly reported that Hamas won the Palestinian parliamentary elections in 2000. It won the elections in 2006.