The reaction of leading Arab states to Donald Trump’s hopelessly unbalanced Middle East “peace plan”, unveiled last week, was muted and mealy-mouthed. It seems the leaders of Egypt, Saudi Arabia and the UAE would sooner abandon the Palestinians than upset their ludicrous Iran-bashing ally in the White House.

Yet one regional leader stood out. Recep Tayyip Erdoğan, Turkey’s president, was furious at what he saw as a US-endorsed Israeli land-grab – and said so. “Giving Jerusalem to Israel is absolutely unacceptable. It ignores Palestinians’ rights and is aimed at legitimising Israel’s occupation,” he said. The Arabs’ silence was “pitiable”.

Erdoğan has long cast himself as a champion of the Palestinian cause. It’s a popular stance with religiously conservative Sunni Muslim supporters of his Justice and Development party. It’s at one with his support for Hamas, the Islamist group that rules Gaza, and its leader, Ismail Haniyeh, whom he feted in Ankara last month. The US, EU and Israel regard Hamas as a terrorist organisation.

Erdoğan is also sympathetic to the Muslim Brotherhood, originally an Egyptian Islamist movement of which Hamas is one of many offshoots. He broke with Egypt after the Brotherhood’s Mohamed Morsi was removed as president by an army coup in 2013. His views, shared by Qatar, have fed his feud with autocratic Gulf monarchies which fear the Brotherhood’s pious, levelling influence.

In truth, Erdoğan, in power now for nearly 20 years, styles himself an everyman leader for all Muslims. Last year, he was named the world’s “most influential Muslim” in a survey by the Royal Islamic Strategic Studies Centre in Jordan. And this role dovetails neatly with his nationalistic, so-called neo-Ottoman foreign policy.

Erdoğan is nothing if not outspoken, often offensively so. But at least he sticks to his beliefs and says what he thinks Simon Tisdall

It is this policy of re-establishing and expanding Turkey’s historical regional influence that is drawing Erdoğan into ever greater conflict with the west. His defiance of Trump over Palestine is of a piece with Turkish actions in Syria and Libya, his collaboration with Russia and Iran, and his regular clashes with the EU.

Maybe Erdoğan, following recent electoral setbacks, hopes to regain domestic popularity by boosting Turkey’s international profile, but it’s more likely that his message of militant pan-Islamic revivalism comes from the heart at a time when Muslims are trapped in multiple global conflicts, from Idlib, Tripoli and Aden to Assam and Xinjiang.

Whatever his motives, Erdoğan is widely deemed a troublemaker in Europe and the US – and the trouble is moving closer to home. Turkey’s attempt to muscle in on energy exploration in the eastern Mediterranean, bolstered by a controversial deal with Libya’s official government, has enraged Greece, Cyprus and their EU allies.

France said last week it was dispatching warships, including an aircraft carrier, to the area following an appeal from Athens. Greece’s defence minister, Nikos Panagiotopoulos, warned of possible “military engagement”, citing rising tensions across the board.

But Emmanuel Macron, France’s president, focused his wrath on Turkey’s intervention in Libya’s civil war. In keeping with the wider regional power contest, Erdoğan has sent militia fighters to help the Tripoli government repulse eastern-based rebels supported by his Arab rivals, including the Saudis and Egypt. This, presumably, was the quid pro quo for the energy deal.

“I want to express my concerns with regard to the behaviour of Turkey at the moment,” Macron declared. “We have seen during these last days Turkish warships accompanied by Syrian mercenaries arrive on Libyan soil. This is an explicit and serious infringement of what was agreed in Berlin” – a reference to last month’s stalemated Libyan peace conference in Germany.

Russia has also sent mercenaries to Libya, to boost the rebels. As this multiparty proxy war intensifies, a key concern for Macron and Moscow (and the US) is the support given by hardline Libyan Islamist groups to Tripoli’s leaders. Yet energy interests aside, the prospect of a Muslim Brotherhood-style regime securing power in Libya must be part of the attraction for Erdoğan.

Turkey’s military intervention in northern Syria last autumn marked another instalment in Erdoğan’s expansionist project – the establishing of control over Syria-Turkey border territory from Idlib and Afrin to Iraq. His twin aims were to punish Kurdish “terrorists” – whom the west greatly values as allies – and prevent another refugee exodus. It was not to fight Isis or like-minded jihadists.

Donald Trump with Israeli prime minister Benjamin Netanyahu on 28 January at the White House. Critics say the president’s ‘peace plan’ favours Israel over the Palestinians. Photograph: UPI/Barcroft Media

But having infuriated the Pentagon and his European allies, Erdoğan is now in dispute with Russia, his erstwhile Syrian collaborator, over its current, murderous regime offensive in Idlib, the last rebel-held province. Erdoğan says Vladimir Putin, Russia’s president, has breached a Turkish-enforced ceasefire agreement there.

By ordering Russian airpower to assist Bashar al-Assad’s forces in attacking civilians, thereby sparking a new northwards refugee surge, Putin is guilty as charged. The row shows how Erdoğan, who angered the US by purchasing Russian missiles, is ready to challenge Moscow too, if it advances his agenda.

“Russia tells us they fight against terrorism. Who are terrorists? The people defending their own lands?” Erdoğan, a backer of Syrian rebels since 2011, said last week. Now he is threatening a new incursion. Are refugees his only concern? Idlib is the last Syrian refuge for thousands of rebel jihadists with ties to al-Qaida and Isis. Is Erdoğan attempting to save them, too?

Erdoğan’s condemnation of Trump’s peace plan is unlikely to be his last word on the subject. In 2018, he accused “brutal” Israeli security forces of employing “methods similar to the Nazis” against “our Gaza brothers”.

Erdoğan is nothing if not outspoken, often offensively so. But at least he sticks to his beliefs and says what he thinks.