The Gaza war has put renewed focus on a two-state solution to the Israeli-Palestinian conflict, still seen by many countries as the path to peace even though the negotiating process has been moribund for years.
More than three months into the deadliest Israeli-Palestinian war yet, Washington has said there is no way to solve Israel's security issues and the challenge of rebuilding Gaza without a Palestinian state.
But Israeli Prime Minister Benjamin Netanyahu has voiced opposition to Palestinian sovereignty, saying he will not compromise on full Israeli security control west of Jordan and that this stands contrary to a Palestinian state.
Obstacles have long impeded the two-state solution, which envisages Israeli and Palestinian states alongside each other.
WHAT ARE TWO-STATE SOLUTION'S ORIGINS?
Conflict occurred in British-ruled Palestine between Jews who had migrated to the area and Arabs. The Jews were seeking a national home as they fled persecution in Europe and cited biblical ties to the land.
In 1947, the United Nations agreed a plan partitioning Palestine into Arab and Jewish states with international rule over Jerusalem. Jewish leaders accepted the plan, which gave them 56% of the land. The Arab League rejected it.
The state of Israel was declared on May 14, 1948. A day later, five Arab states attacked. The war ended with Israel controlling 77% of the territory.
Some 700,000 Palestinians fled or were driven from their homes, ending up in Jordan, Lebanon and Syria as well as in Gaza, the West Bank and East Jerusalem.
In a 1967 war, Israel captured the West Bank, including East Jerusalem, from Jordan and Gaza from Egypt, securing control of all territory from the Mediterranean to the Jordan valley.
The Palestinians remain stateless, with most living under Israeli occupation or as refugees in neighbouring states. Some - mostly descendents of Palestinians who remained in Israel after its creation - have Israeli citizenship.
HAS A DEAL EVER BEEN CLOSE?
The two-state solution was the bedrock of the U.S.-backed peace process ushered in by the 1993 Oslo Accords, signed by Yasser Arafat of the Palestine Liberation Organization (PLO) and Israeli Prime Minister Yitzhak Rabin.
The accords led the PLO to recognise Israel's right to exist and renounce violence and to the creation of the Palestinian Authority (PA), which has limited self-autonomy in the West Bank and Gaza Strip.
Palestinians hoped this would be a step towards an independent state, with East Jerusalem as the capital.
The process was hit by rejection and violence on both sides.
Hamas, which opposed the process, carried out suicide attacks which killed scores of people.
Rabin was assassinated in 1995 by an Israeli ultra-nationalist opposed to his peace policies.
In 2000, U.S. President Bill Clinton brought Arafat and Israeli Prime Minister Ehud Barak to Camp David to clinch a deal, but the effort failed.
The fate of Jerusalem, deemed by Israel as its "eternal and indivisible" capital, was the main obstacle. The talks had also grappled with the borders of a Palestinian state, along with the fate of Palestinian refugees and Jews who had settled in the territories captured in 1967.
The conflict escalated as the Second Intifada, or uprising, began. U.S. administrations sought to revive peace-making - to no avail.
WHAT MIGHT PALESTINE LOOK LIKE?
Advocates of the two-state solution have envisaged a Palestine in the Gaza Strip and West Bank linked by a corridor through Israel.
Two decades ago, details of how it might work were set out in a blueprint by former Israeli and Palestinian negotiators.
Israel would annex big settlements and cede other land in a swap, and resettle Jewish settlers in Palestinian sovereign territory outside there.
A multinational force working alongside Palestinian security forces would monitor Palestine's border crossings to Jordan and Egypt, as well as air and sea ports.
U.S. President Joe Biden and Egyptian President Abdel Fattah al-Sisi have both mentioned the idea of a demilitarised Palestinian state - an idea Abbas has never publicly rejected or accepted but which Hamas rejects.
HOW BIG ARE THE OBSTACLES?
The obstacles have grown with time.
While Israel withdrew settlers and soldiers from Gaza in 2005, Jewish settlements expanded elsewhere. Palestinians say this undermines the prospects of a viable state.
The Israeli organisation Peace Now said in September the number had grown from 250,000 in the West Bank and East Jerusalem in 1993, to 695,000 three decades later.
During the Second Intifada Israel also constructed what it described as a barrier to stop Palestinian attacks. Palestinians call it a land grab.
The PA led by President Mahmoud Abbas administers islands of West Bank land enveloped by a zone of Israeli control comprising 60% of the territory, including the Jordanian border and the settlements - arrangements set out in the Oslo Accords.
In that zone, known as Area C, Israel has full control.
The PA administers civil affairs and internal security in a zone known as Area A, amounting to about a fifth of the territory and including the main Palestinian cities.
In the remaining fifth - Area B - it runs civil affairs while Israel is responsible for security.
Israel has carried out raids in Palestinian urban centres including Ramallah, where the PA is based, during the war.
Politics has added to the complications.
Netanyahu's government is the most right-wing in Israeli history and includes religious nationalists who draw support from settlers. Finance Minister Bezalel Smotrich said last year there was no such thing as a Palestinian people.
Hamas won elections in 2006 and a year later drove forces loyal to Abbas out of Gaza, fragmenting the Palestinians.
Hamas' 1988 founding charter calls for Israel's destruction and it refuses to recognize Israel. Hamas leaders have at times offered a long-term truce in return for a viable Palestinian state on all territory occupied by Israel in 1967.
Israel regards this as a ruse.
In 2017, a document issued by Hamas said it agreed to a transitional Palestinian state within frontiers pre-dating the 1967 war, although it still opposed recognizing Israel's right to exist or ceding any Palestinian rights.
IS THERE A WAY FORWARD?
Gaza's fate is the immediate question.
Israel aims to annihilate Hamas and says it will not agree to any deal that leaves it in power. Netanyahu has said Gaza must be demilitarized and under Israel's full security control.
He has said he does not want Israel to govern Gaza or re-establish settlements there.
Hamas says it expects to survive and has said any arrangements for Gaza that exclude it are an illusion. Hamas says it is ready for talks with Abbas's Fatah faction to form a unity government. Such talks have previously failed.
Washington, which deems Hamas a terrorist group, has said it wants to see governance of Gaza and the West Bank reconnected under a revitalized PA.
Netanyahu has said he will continue to insist on full Israeli security control west of the Jordan river - a position he said had prevented the establishment of a Palestinian state that would have been "an existential danger to Israel".
In his 2022 autobiography, Netanyahu set out other ideas at odds with Palestinian aspirations, including an airport for Palestinians that "could be located in Jordan or elsewhere".
He called for a change of approach from "territorial continuity" in Palestinian areas to "transportational continuity" with "docks, train links, overpasses and underpasses" enabling Palestinian freedom of movement.
A spokesperson for Abbas said Netanyahu's recent statements showed Israel was not "interested in peace and stability". Hamas official Osama Hamdan said on Jan. 22 Palestinians would not accept anything less than a sovereign state with Jerusalem the capital.
IS THERE AN ALTERNATIVE?
As the two-state solution has floundered, talk of a one-state solution has risen. Some Palestinians, convinced Israel will never cede them sovereignty, have advocated switching to a struggle for rights within a single country spanning Israel and the land it occupied in 1967.
Critics say it is unrealistic, noting the main Palestinian factions do not back it and Israel would never accept an idea that could jeopardise its existence as a Jewish state.
U.N. Secretary General Antonio Guterres, in a Jan. 23 speech, said the two-state solution remained the only way to address the aspirations of Israelis and Palestinians. He criticised "clear and repeated rejection of the two-state solution at the highest levels of the Israeli government".
"This refusal, and the denial of the right to statehood to the Palestinian people, would indefinitely prolong a conflict that has become a major threat to global peace and security."
