Recep Tayyip Erdogan, the Turkish President, once famously likened democracy to a train on “which you travel until you reach your destination, and then get off”. Following the events of this Sunday’s referendum in Turkey, it seems that Mr Erdogan has finally reached his station.

Despite allegations of widespread fraud in the vote-counting and unprecedented challenges by the main opposition parties who refuse to accept the official referendum result of 51.4 per cent of Turkish voters in favour, the President claimed victory and is going forward with the transformation of Turkey to a presidential regime, one which gives him wide-reaching powers.

But even at the peak of his powers, President Erdogan is constrained, at home and abroad. On the domestic front, he cannot ignore the fact that, even after fighting the referendum campaign on what the Organisation for Security and Co-operation in Europe termed a “unlevel field”, and all the vote-counting irregularities, his opponents managed 48.6 per cent of the vote.

To assume the new powers of the presidency, he has to win another election in 2019, an election which will no doubt take place under even greater scrutiny, and in which he stands to lose not only the enhanced position he has been trying to build for over a decade, but his legitimacy. For now, however, he is doubling down.

Mr Erdogan has little to worry about from challenges to the referendum results. The Turkish legal system, ruthlessly purged of his political opponents, is unlikely to uphold the challenges. But he has more pressing worries across the border in Syria.

Turkey’s Nato partner, the United States, is about to lead an allied push against the Daesh stronghold in Raqqa. The main forces on the ground are the Kurdish-led Syrian Defence Forces, to which Mr Erdogan is resolutely opposed for fear of a Kurdish autonomy taking shape on his border. He wants to launch an offensive of his own, with more friendly Kurdish forces against Raqqa and is seeking backing from Russia. But the Kremlin’s support will come with a price — relinquishing Mr Erdogan’s long-held opposition to Syrian President Bashar Assad remaining in power.

This is not the first time recently where Mr Erdogan has been forced to acknowledge his limitations in the region. In Turkey’s rapprochement with Israel last year, it gave up its demand to “open up” the Gaza Strip and agreed to limit the operations of Hamas’s office in Turkey. Senior officials in Jerusalem and Ankara agree that, ultimately, the Turkish President had to give up most of his demands to rebuild the co-ordination with Israel which is important to Turkey’s regional interests.

Now he will have to make difficult choices to remain a power-player in Syria’s future. Both Vladimir Putin and Donald Trump phoned him to congratulate him on his referendum win. It was a reminder that not all his problems can be solved by stuffing ballot boxes.

Beneath Mr Erdogan’s bombastic and antagonistic rhetoric is ruthless pragmatism and a calculating political mind. He knew that — in a country facing both Kurdish and Islamist terror campaigns and still in the state of emergency called in the wake of last year’s failed military coup — he could get away with a fraudulent referendum. Once powerful military and legal establishments are today powerless to oppose him.

He also feels that, with the current turmoil in the European Union, he can challenge its leaders , call them “Nazis” and “Crusaders” and use them as convenient hate-figures to rally his base. Earlier in his long stint in power, he trod with much more care around the army and made sweeping democratic reforms to mollify the EU. He is aware that the power-balance can change. Now he is much more careful with the White House, the Kremlin and Israel than just a couple of years ago.

Even according to the skewed official referendum results, Mr Erdogan lost the support of Turkey’s main cities, including Ankara, Istanbul and Izmir. With the Turkish economy teetering on the brink of a recession, he can ill afford turmoil in the major commercial centres, which are also the hubs of the crisis-struck tourism industry. Without political stability and a respite from the terror attacks, a decade-and-a-half of economic growth and relative prosperity will come to an abrupt end and Mr Erdogan will lose many of his remaining supporters.

Isolated at the top of a narrow hierarchy, Turkey and its President’s fate are intertwined, dependent on his ability now to rein in his autocratic tendencies and rebuild bridges to trade partners in Europe and the estranged half of his own nation.