(Reuters) - A rift between President Joe Biden and Israeli Prime Minister Benjamin Netanyahu over Gaza red lines has set up a potential showdown between the two leaders, raising questions about whether the US might restrict military aid if Israel goes ahead with a ground offensive in the south of the enclave.
The United States has been a staunch ally of Israel since President Harry Truman became the first world leader to recognise the newly established state in 1948.
But strains have emerged in the normally solid ties over the decades. Here are milestones:
1948
President Harry Truman becomes the first world leader to recognize the newly-established Israel.
1956
Furious at Israel's capture of the Sinai Peninsula and Gaza Strip from Egypt in a campaign with France and Britain, the administration of President Dwight Eisenhower insists on unconditional Israeli withdrawal and threatens to suspend vital US financial aid to Israel unless it withdraws.
1967
The US stands behind Israel in a war with surrounding Arab states. But relations are jolted by Israel's attack in international waters on the Liberty, a US spy ship. Thirty-four American seamen are killed and 174 wounded.
1973
President Richard Nixon rushes to Israel's aid with an airlift of military hardware after Egypt and Syria, which lost territory in the 1967 conflict, launch the 1973 war.
1975
The US administration of President Gerald Ford threatens to reappraise US ties with Israel unless it signs a "disengagement" treaty with Egypt to pull back from the Sinai peninsula, captured in 1967.
1979
President Jimmy Carter hosts signing of peace treaty between Israel and Egypt, concluded in talks at Camp David.
1981
The US condemns Israel's bombing of Iraq's Osirak nuclear reactor.
1982
In a telephone call to Israeli Prime Minister Menachem Begin, President Ronald Reagan expresses what a spokesman calls "outrage" over Israeli bombing raids in Beirut during a war in Lebanon, and pressures him into a ceasefire.
1990
Secretary of State James Baker says US growing weary of Israeli foot-dragging over peace negotiations with the Palestinians and recites White House telephone number, urging both sides "to call us when you are serious about peace".
1991
President George Bush Sr. pressures Israel to stay out of first Gulf War, concerned that an Israeli attack on Iraq would cause a US-led coalition to disintegrate.
Washington withholds $10 billion in loan guarantees sought by Israel to absorb the immigration of Soviet Jews, piling pressure on Prime Minister Yitzhak Shamir to attend the Madrid peace conference. Bush cites the best interests of the peace process in justifying the postponement, and says he will not grant the guarantees unless Israel freezes settlement building.
1992
Bush approves Israel's loan guarantees request after Prime Minister Yitzhak Rabin offers a limited curtailment of settlement building.
1993
President Bill Clinton hosts a handshake between Rabin and Palestinian leader Yasser Arafat at the signing of a Declaration of Principles on interim Palestinian self-government.
1998
Clinton hosts summit between Arafat and Prime Minister Benjamin Netanyahu at Wye River, Maryland. Netanyahu agrees to hand over more occupied land to Palestinian control.
2003
President George W. Bush announces "road map" peace plan, three years after start of Palestinian uprising, setting an outline for an end to violence and return to statehood talks.
2004
Bush tells Israeli Prime Minister Ariel Sharon "existing major Israeli population centers" – an indirect reference to Jewish settlement enclaves in the West Bank – make it "unrealistic" to expect Israel to return to armistice lines drawn in 1949.
2009
Bush tells Israel's parliament the unbreakable bond between Israel and the US runs deeper than any treaty and is grounded in the shared link to the Bible.
2010
The administration of President Barack Obama is furious with Israel for announcing the building of more settler homes around Jerusalem during a visit by Vice President Joe Biden. Secretary of State Hillary Clinton calls the move "insulting".
2011
Netanyahu lectures Obama in the White House Oval Office days after Obama stated publicly that "the borders between Israel and Palestine should be based on the 1967 lines".
2015
Obama says the international community does not believe that Israel is serious about a two-state solution.
2016
Obama, in the final weeks of his presidency, allowed a UN Security Council resolution condemning Israeli settlement building to be adopted by withholding the US veto. It breaks with a history of US shielding Israel at the UN.
2017
Reversing decades of US policy, President Donald Trump recognises Jerusalem as Israel’s capital. The new US embassy opens in 2018.
2019
The Trump administration recognizes Israeli sovereignty over the Golan Heights, territory captured from Syria in the 1967 war. The US is the only country to do this.
2023
Oct. 7 - US President Joe Biden offers Israel "all appropriate means of support" after the Palestinian militant group Hamas launches its Oct. 7 attack on Israel, and warns "any party hostile to Israel" not to seek advantage.
Dec. 12 - Biden warns Israel it was losing international support because of its "indiscriminate" bombing of civilians in its war against Hamas militants.
2024
Feb. 8 - Biden says he seeks a "sustained pause in the fighting".
Feb. 11 - Biden tells Netanyahu Israel should not launch a military operation in Rafah without a credible plan to ensure the safety of the roughly 1 million people sheltering there.
Feb. 27 – Netanyahu says he has consistently resisted pressure to end the war prematurely and this stand has popular US support.
March 9 - Biden says Israel’s threatened invasion of Rafah would be his “red line” for Netanyahu but then backtracks, saying there is no red line and "I’m never going to leave Israel." Biden says his message to Netanyahu about civilian casualties is that he is “hurting Israel more than helping” by acting in a way "contrary to what Israel stands for."
March 12 - Netanyahu says that Israel would press forward with its military campaign into Rafah.