It is harder than it ought to be, explaining why recognising Jerusalem as Israel’s capital is a bad idea. The city has been Israel’s centre of government since 1948. While most countries have held off, the US Congress passed a Jerusalem Embassy Act in 1995, which included a line recognising the city as Israel’s capital. President Trump campaigned on a promise to implement the act, and though he has previously followed other presidents in signing waivers suspending it, this week he has missed two deadlines, suggesting that he is strongly tempted to give it the go-ahead.

If he does, it will derail the last hope of peace, according to the Palestinian Authority, and degrade US influence in the world, as countries including Turkey have warned. These may not seem like persuasive arguments. The US has willingly surrendered much of its standing; there is no peace process; and the reputation of both Turkey and the Palestinian Authority is low. But recognising Israel’s current version of Jerusalem would create enormous and new insoluble problems without addressing the real issues that beset the city.

Israel’s mutant version of Jerusalem is far larger than any historical iteration of the city

Israel only captured the old city and adjoining Palestinian suburbs such as Silwan in 1967. A hastily written law was pushed through the Knesset declaring the territory had been annexed to Israel, and the city of Jerusalem had been “reunited”. According to the Geneva Conventions, territory acquired through war is under “hostile military occupation” in a formula that has endured since the defeat of fascism. Successive Israeli governments have argued the terms of the conventions do not apply to Jerusalem. However, in December 2016, the UN took a vote reaffirming that the Palestinian territories were under hostile occupation. Israel’s attempt to pressure Trump’s transition team in the runup to the vote has now come within the scope of the Mueller investigation.

Q&A Why is recognising Jerusalem as Israel's capital so contentious? Show Hide Of all the issues at the heart of the enduring conflict between Israel and the Palestinians, none is as sensitive as the status of Jerusalem. The holy city has been at the centre of peace-making efforts for decades. Seventy years ago, when the UN voted to partition Palestine into Jewish and Arab states, Jerusalem was defined as a separate entity under international supervision. In the war of 1948 it was divided, like Berlin in the cold war, into western and eastern sectors under Israeli and Jordanian control respectively. Nineteen years later, in June 1967, Israel captured the eastern side, expanded the city’s boundaries and annexed it – an act that was never recognised internationally. Israel routinely describes the city, with its Jewish, Muslim and Christian holy places, as its “united and eternal” capital. For their part, the Palestinians say East Jerusalem must be the capital of a future independent Palestinian state. The unequivocal international view, accepted by all previous US administrations, is that the city’s status must be addressed in peace negotiations. Recognising Jerusalem as Israel’s capital puts the US out of step with the rest of the world, and legitimises Israeli settlement-building in the east – considered illegal under international law. Photograph: Thomas Coex/AFP

When the organisers of the 2018 Giro d’Italia declared last week that the cycle race, its opening leg in Israel, would start in “west Jerusalem”, they received a sharp rebuke from Israeli minister Miri Regev. “In Israel’s capital,” she declared, “there is no east and west.” Anyone visiting Jerusalem would quickly see how wrong she is. The presence of both the army and border police, a militarised gendarmerie, underline that much of the city is under military control. When I was researching in the archives of St George cathedral school, the secretary told me how frightened she was when the school bell rang because she did not know if the children would get home safely, or be picked up and beaten or arrested. Border police recruits are little more than teenagers themselves. Their behaviour, and their treatment of arrested children, was the subject of a bill presented to the US Congress last month. But it is not simply the treatment of people in Jerusalem that is the problem.

The city has twice been enlarged in the 50 years since its annexation, a decision taken each time through acts of parliament. Israel’s mutant version of Jerusalem is far larger than any historical iteration of the city. It contains Palestinian towns, villages and refugee camps, as well as Israeli settlements. The Geneva Conventions exist in parallel with human rights legislation, making Israel responsible for the welfare of many hundreds of thousands of people. Within these city limits, Israel presides over deeply deprived and lawless communities, where substance abuse is endemic and health services are poor or non-existent. These zones have no proper sewage provisions, and neither do the adjoining Jewish zones. The effluent has turned the Kidron stream into an open sewer, polluting the desert and the Dead Sea.

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Jerusalem is not divided, impoverished and ungoverned because international law makes it so: it is a situation that flows from the territorial ambitions unleashed by war. Successive Israeli governments have been unable to cope with problems they have created, and lacked the political will to make a peace that will see Palestinians controlling their own lives. Rather than honestly own the situation, Israel’s leaders have tried to muddy the legal framework that defines the state of the city.

Q&A What is the history of the Palestinian reconciliation efforts? Show Hide The two main Palestinian parties – the Fatah faction of Palestinian Authority president Mahmoud Abbas and the Islamist militant group Hamas – have run separate governments in the West Bank and Gaza respectively since 2007. The situation emerged after Hamas defeated Fatah in parliamentary elections in 2006. Fatah refused to recognise the result, leading to a near-civil war that saw Hamas push Fatah out of Gaza. Numerous attempts at reconciliation have ensued but the latest effort looks the most serious yet. The issue of who controls the borders and runs government ministries is a key test, not least in loosening the Israeli blockade on Gaza, imposed after Hamas took control.

Responsibility for land border crossings – in a coastal strip without a commercial sea port or airport – is crucial, as Palestinians and goods can only cross by these checkpoints. Both Egypt and Israel will want to ensure that no arms reach Hamas and other groups.

We live in a climate where international law is under threat. Human rights are attacked as a UN-sponsored industry that enriches the corrupt and lazy, while tying the hands of dynamic wealth creators. Serial attempts to degrade the international order have made Israeli politicians the darlings of the political right, and won over businessmen who despise legal restraints.

Trump is a creature of the right and a friend of toxic financiers. One can see why he would argue for appeasement, and legitimise Israel’s acquisitions. But it would be a sordid retreat into chaos and murder that would fuel the political and moral catastrophe in a city beloved by the world.

• Nicholas Blincoe is the author of Bethlehem: Biography of a Town (Nation Books).