US President Donald Trump reversed decades of US policy when he recognised Jerusalem as the capital of Israel, with many saying this would jeopardise the chances of peace between Israel and the Palestinians.

But his controversial decision didn't come out of nowhere.

In September 2016, Mr Trump promised Israeli Prime Minister Benjamin Netanyahu that he would do exactly this if elected.

Now, he says he's delivering:

"While previous presidents have made this a major campaign promise, they failed to deliver."

You might be surprised to discover one of the people he could be talking about is his predecessor Barack Obama.

Firstly, here's what the United States policy was before now

Confusingly, the US Congress passed a law in 1995 called the Jerusalem Embassy Act which described Jerusalem as the capital of Israel and said it should not be divided.

That law required the US embassy to be moved to Jerusalem by 1999.

But this hasn't happened because every six months, successive presidents have signed a waiver to keep the US embassy in Tel Aviv for national security reasons.

As well, successive presidents have backed negotiations between Israel and the Palestinians on the status of Jerusalem.

However, that's not always what they said before they took office.

In 2008, then Democratic candidate Barack Obama called Jerusalem the 'capital of Israel'

Then-senator Barack Obama speaks at the AIPAC conference on June 4, 2008. ( Reuters: Jason Reed )

In his last press conference as President, Mr Obama warned that moving the US embassy to Jerusalem could have "explosive" results.

His administration had kept to America's long-held policy on Jerusalem:

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But this is what Mr Obama told pro-Israel lobby group the American Israel Public Affairs Committee (AIPAC) on June 4, 2008, in his first foreign policy speech after capturing the Democratic nomination the day before:

"Let me be clear. Israel's security is sacrosanct. It is non-negotiable. "The Palestinians need a state that is contiguous and cohesive, and that allows them to prosper — but any agreement with the Palestinian people must preserve Israel's identity as a Jewish state, with secure, recognised and defensible borders. "Jerusalem will remain the capital of Israel, and it must remain undivided. I have no illusions that this will be easy."

However, the then-senator and presidential hopeful backtracked almost immediately.

When asked shortly afterwards by CNN whether Palestinians had no future claim on the city, Mr Obama responded:

"Well, obviously, it's going to be up to the parties to negotiate a range of these issues. And Jerusalem will be part of those negotiations."

In 2000, then Republican candidate George W Bush promised to move the US embassy to Jerusalem

George W Bush had hoped to secure a deal on a Palestinian state. ( Reuters: Lucy Nicholson )

He too made the comment to AIPAC:

"Something will happen when I'm president: as soon as I take office I will begin the process of moving the US ambassador to the city Israel has chosen as its capital."

But this never happened during his eight years as president.

He sponsored peace negotiations between Israel and the Palestinians in the hope of securing a deal on a Palestinian state before he left office.



In 1993, former president Bill Clinton also came to office saying he supported 'the principle' of moving the US embassy to Jerusalem

Former president Bill Clinton said he too wanted to move the US embassy. ( Chip East : Reuters )

But this wasn't a promise. In 2000, in his last year as president, Mr Clinton told Israeli reporters:

"I have always wanted to move our embassy to west Jerusalem. We have a designated site there. I have not done so because I didn't want to do anything to undermine our ability to help to broker a secure and fair and lasting peace for Israelis and for Palestinians."

The Trump Administration says it is looking to identify a site for the US embassy in Jerusalem. The move is expected to take years.

ABC/Reuters