Two foreign policy decisions by Donald Trump has dramatically ramped up tension in the Middle East and resulted in the deaths of scores of people. But does a US president really have so much power that he on his own can decide weighty matters that will inevitably impact his own country? The answer is yes, he has. At least when it comes to these two particular decisions – the dumping of the Iran nuclear deal and the moving of the US Embassy to Jerusalem. And Trump didn’t have to resort to his favourite political instrument – the executive order -- to achieve this dramatic shift in US foreign policy. Take the Iran nuclear deal, which after a decade of wrangling was finally signed in 2015 between the US, Britain, Germany, France, Russia, China and Iran. Under the fragile pact, Tehran agreed to rein in its controversial nuclear programme in return for an easing of tough economic sanctions. Signatories to the accord had been certifying Iran’s compliance with the terms of the accord every six months. To pull the plug on the deal and raise the very real prospect of a resumption of Iran’s nuclear programme, all Trump had to do was in early May refuse to issue the certification.Trump then went on to issue, with the flourish of his pen, an executive order reimposing sanctions on the Islamic republic. This he has the power to do without Congress approval. Political commentators believe that Trump’s decision, which makes no logical sense since it is unsupported by the other signatories and unnecessarily heightens the risk of Iranian proliferation, stems from his overriding ambition to dismantle the legacy of his predecessor, Barack Obama. On the question of the status of Jerusalem, Obama insisted that this was a question for Israelis and Palestinians themselves to resolve. Trump, while campaigning for the presidency, on the other hand promised that he would recognise Jerusalem as the Israeli capital and move the US Embassy from Tel Aviv to the historical city. In December, he made good his recognition promise and on Monday the embassy relocation took place. Palestinians, who hope to claim part of the city as their future capital, had warned that such a move would spark outrage and lead to fresh bloodletting. And indeed it did, with dozens of Palestinian protestors killed and thousands others injured in clashes with Israeli security forces in Gaza on Monday – even as the embassy was being opened. It was the bloodiest day in seven weeks of violent demonstrations on the Gaza border launched by Palestinians to protest Israel’s economic blockade of the territory. The violence, further inflamed by the US Embassy relocation, is not expected to abate any time soon. Middle Eastern leaders slammed the US move as provocative while 128 countries had condemned it when Trump’s decision was discussed at the United Nations in December. The international community considers East Jerusalem occupied territory and all countries have refrained from setting up their embassies in the city, choosing Tel Aviv instead. Key US allies Germany, Britain and France boycotted Monday’s inauguration ceremony. All three nations have also condemned Trump’s decision to torpedo the Iran nuclear deal. As with his decision on Iran, Trump didn’t need the approval of the Congress to change decades-old US foreign policy. In fact, he merely allowed a 1995 law to come into effect. The Jerusalem Embassy Act was passed by Congress in 1995 but then President Bill Clinton refused to sign it, saying it “could hinder the peace process” – though it nevertheless became law. The Act demanded that the US move the embassy from Tel Aviv to Jerusalem by a set deadline,but allowed the move to be put off for six months at a time as long as the president “determines and reports to Congress in advance that such suspension is necessary to protect the national security interests of the United States.” Since the law was passed, successive presidents have every six months informed Congress that such suspension is indeed necessary – and the embassy remained in Tel Aviv. Until Trump decided last December to recognise Jerusalem as Israel’s capital and authorise the relocation of the embassy. Trump, by killing off the Iran nuclear deal and taking Israel’s side on the question of Jerusalem, has waded into the turmoil roiling the Middle East. And no one or nothing can stop him, not even the powerful US Congress.