With the largest Jewish population outside of Israel and a growing Arab-American population, the United States has unique social, cultural and diplomatic ties to Israel and the Palestinian territories.

Historically, Washington has viewed Israel as a crucial political and economic ally in the oil-rich Middle East, and has provided Israel with the highest amount of financial and military assistance of any other foreign country. These days, however, the United States has used its leverage to urge Israel to resolve the Palestinian issue and move forward on plans for an autonomous Palestinian state.

Since the end of World War II, the United States has been one of the leading nations to encourage, facilitate, and arbitrate cease-fire accords between Israelis and Palestinians.

Other countries, notably France, Russia, Norway, Jordan, and Egypt, participate extensively in peace efforts, often working in concert with the United States and the United Nations.

The United States has pointed to its large financial assistance Israel and Egypt as evidence of its commitment to secure a lasting peace and foster democracy and economic growth in the region.

U.S. financial and military assistance quadrupled after Syria and Egypt, supported by the Soviet Union, invaded Israel on Oct. 6, 1973. Prime Minister Golda Meir asked U.S. President Nixon for immediate military assistance for her army that had been decimated in the 1973 Yom Kippur War and the 1967 Israeli war against the Egyptian and Syrian armies.

Following the 1973 war, Egypt and Israel began to quietly explore the possibility of a diplomatic peace. Under the guidance of U.S. President Carter, cease-fire talks between Israeli Prime Minister Menachem Begin and Egyptian President Anwar Sadat opened five years later at Camp David, in the Catoctin Mountains of Maryland.

The meetings ended with the Camp David peace accords, based on U.N. resolutions 242 and 338, which stipulated that Israel would relinquish territory to neighboring Arab nations in exchange for recognition of Israel's national sovereignty and security. The Camp David accords ended the war between Egypt and Israel and laid the foundation for the so-called "land-for-peace" deals between Palestinians and Israelis.

During the 1980s, Washington continued to dispatch high-level officials, such as secretaries of state George Shultz and James Baker and Ambassador Philip Habib, to the region in attempt to initiate serious discussions between the Israelis and Palestinians. During this time, Shultz reopened communication channels between U.S. and Palestinian governments for the first time in more than 13 years.

During the Persian Gulf war, relations between the United States and the Palestine Liberation Organization soured when PLO Chairman Yasser Arafat supported Iraq's invasion of Kuwait and its threat to attack Israel.

Following U.S. victory in the Persian Gulf war, U.S. President George H.W. Bush and Soviet President Michael Gorbachev sponsored a peace conference in Madrid to address the conflict between Israel and Palestine. The conference in 1991 rejuvenated the Israeli-Palestinian negotiations.

Over the next two years, the United States and other nations moderated discussions between Israeli and Palestinian leaders, and, in 1993, at the 11th round of peace talks, Israeli Foreign Minister Shimon Peres announced that Israel and the PLO reached a land-for-peace deal in Oslo.

That fall at the White House, Israeli Prime Minister Yitzhak Rabin and Palestinian Authority Chairman Yasser Arafat oversaw the signing of the agreements reached at Oslo. Under the so-called Oslo accords, Arafat recognized Israel's right to exist and renounced the use of violence against the Jewish state. In return, Israel promised to allow for Palestinian self-rule in sections of the Gaza Strip and West Bank.

In 1995, Israeli and Palestinian leaders met again in Washington, D.C. with President Clinton to discuss specific steps to gradually transfer autonomy to the newly formed Palestinian Authority in the West Bank and Gaza Strip.

However, the United States lost a key ally when an Israeli extremist opposed to the Oslo accords assassinated Rabin in November 1995.

After a year of frequent talks and increasing violence in the Middle East, President Clinton led a face-to-face meeting between Arafat and Israeli Prime Minister Benjamin Netanyahu at the Wye River Conference Center in Maryland to press for the implementation of the final elements in the Oslo accords. The leaders, meeting in the fall of 1998, reaffirmed their commitment to the obligations as set forth in the Oslo settlement.

Additionally, in an effort to improve U.S. relations with the Palestinian government, President Clinton spoke to the Palestinian Legislative Council in the Gaza Strip, the first time a U.S. president addressed the council.

As Israeli and Palestinian peace efforts waned amid increasing outbursts of violence, President Clinton, at the end of his second term, assigned former Sen. George Mitchell to head a fact-finding mission to investigate roots of the conflict.

The administration of President George W. Bush endorsed the Mitchell Report on Mideast violence and, as evidence of its commitment to securing peace between Israelis and Palestinians, maintained its traditional role of sending high-level officials to push for a lasting truce.

Indeed, in February 2001 President Bush signaled continued high-level U.S. engagement when he sent his top diplomat, Secretary of State Colin Powell, to the Middle East to meet another new leader, the freshly anointed Israeli Prime Minister Ariel Sharon, and Palestinian President Yasser Arafat. By November of that year, President Bush became the first U.S. president to publicly call for two states, Israel and Palestine, existing side by side.

But violence had already begun to creep back into the landscape of the Palestinian-Israeli relationship, and by early 2002 it had grown such that it had a name -- the second intifada. It witnessed an Israeli reoccupation of Palestinian West Bank and Gaza towns and villages, in response to attacks by Palestinians on Israeli targets, and the deaths of dozens of civilians on both sides.

A major byproduct of the renewed strife was a significant shift in U.S. policy toward the Palestinians, specifically their leader. Arafat, one of the most frequent visitors among foreign leaders to the Clinton White House, became unwelcome in Washington, perceived by the Bush administration as the Israelis saw him -- a terrorist.

On June 24, 2002 President Bush went a step further, calling on Palestinians "to elect new leaders, leaders not compromised by terror," a thinly veiled call for Arafat's ouster. The president also detailed steps he saw as necessary for a return to peace between the two parties -- chief among them a Palestinian renunciation and cessation of terrorism, and the end to Israeli settlement expansion.

Those steps were codified in the so-called road map to peace, released as a formal plan in April 2003. Within a month, the Palestinians had named a new prime minister, Mahmoud Abbas, or Abu Mazen, one of the top Oslo negotiators, paving the way to a major summit of Palestinian, Israeli, U.S. and Jordanian leaders in the Jordanian port city of Aqaba.

But the hope that accompanied those events faded quickly, and the road map became the target of Palestinian criticism, perceived as yet another U.S. effort that pressured Palestinians for Israeli benefit. By September 2003, Abbas had resigned, a victim partly of clashes with Arafat over the control of Palestinian security forces. But Palestinians also saw in him a leader handicapped by and unable to counter the strong Bush-Sharon relationship, therefore unable to improve daily Palestinian life.

It would not be until early 2004 that any real energy was injected back into the quest for a solution to the Israeli-Palestinian conflict. When it did come, it took the form of a U.S.-backed plan announced by Sharon to withdraw all Israeli settlers and supporting military personnel from Gaza and four West Bank villages.

The plan had undergone public debate for months. But with little direct U.S. involvement or Israeli coordination with Palestinians, Palestinians ultimately judged it to be a unilateral effort by Israel to force a settlement on Israeli terms. When President Bush wrote Sharon in support of the plan in April 2004, he urged all parties to consider that "[i]n light of new realities on the ground, including already existing major Israeli populations centers, it is unrealistic to expect that the outcome of final status negotiations will be a full and complete return" to the borders before 1967. Palestinians interpreted that as U.S. sanctioning of an Israeli annexation of parts of the West Bank.

By the time the plan began to grow into reality, the United States was fighting an insurgency in Iraq, leaving little time or energy to devote to the Israeli-Palestinian conflict. That remained the case when, in November 2004, Yasser Arafat -- the man who put the Palestinian cause on the public agenda but failed to secure its spot on the map - died from an unidentified disease. President Bush called on the Palestinians once again to choose a leader who rejected violence as a successor to Arafat.

Palestinians did just that when they elected Abbas in January 2005, and preparations soon gave way to another White House visit amid hopes of a breakthrough in the conflict. But hopes began to fade as violence perpetrated by Palestinians and Israelis continued that summer.

However, in a series of historic events, Israel in August made good on its commitment to withdraw all its settlers and troops from the Gaza Strip and parts of the West Bank, and Sharon left his right-wing Likud Party to form a new, more moderate one called Kadima. His new party was based on the premise that the Israeli public favored further disengagements from Palestinian territories as long as there was, in their opinion, no Palestinian negotiating partner.

The move was largely welcomed by the Bush administration, as an acknowledgement of Sharon's pursuit of an end to the stalemate. But the administration also shared Palestinian concerns that the Gaza, West Bank and any future unilateral Israeli withdrawals would force a non-negotiable settlement on the Palestinians.

By January 2006, Sharon had faded from the political scene, felled by a massive stroke that left him permanently incapacitated. Later that month, a fractured Palestinian ruling class, Fatah, saw its defeat at the hands of a disciplined political effort by the militant group Hamas, whose charter calls for Israel's destruction, and who won parliamentary elections on an anti-corruption and social services platform.

The victory brought calls, led by Israel and the United States, for the diplomatic and financial isolation of any new Hamas-led government, and essentially put an end, for the time being, to any contacts between the Palestinians and the United States and Israel. That sentiment continued after the March 2006 election victory by Sharon's Kadima Party, and the selection of his successor, Ehud Olmert, who pledged to complete Israel's withdrawal from most of the West Bank by 2010.

-- Updated by David Butterworth for the Online NewsHour