Turkish President Recep Tayyip Erdogan was on November 10 accused of exploiting a judicial crisis in “an attempt … to overhaul the constitutional order”.

The claim was made by the new leader of Turkey’s main opposition Republican People’s Party (CHP), Ozgur Ozel, as Erdogan stoked a row in which Turkey’s top appeals court, the Court of Cassation, has made a criminal complaint against judges of the Constitutional Court, following their ruling that parliamentarian Can Atalay should be released from prison.

Erdogan has gone as far as calling for a new constitution to resolve the unprecedented clash. Ozel, however, called on Turkey’s leader to protect the existing constitution, saying: "The president, who takes his power from the constitution, is supporting the Court of Cassation's actions ignoring the constitution."

The battle between the courts erupted as the European Commission, in an annual report on Turkey in relation to its EU membership bid, accused Ankara of "serious backsliding" on democratic standards, the rule of law, human rights and judicial independence. Turkey’s application to join the EU has been in the deep freeze for several years because of Erdogan’s increasingly authoritarian rule. The report means it will stay there.

The struggle between the courts has, meanwhile, triggered a new worry—Turkey’s bid to bring in foreign capital to help pull the country out of its longstanding economic crisis could be imperilled if global investors are deterred by the sight of the rule of law becoming a battleground for the nation’s top courts.

Geopolitical intelligence firm Stratfor said in a November 9 note to investors: “This clash between Turkey's top courts may cause a judicial crisis and a lack of standardized interpretations of regulations. Without uniform regulations, foreign capital is unlikely to increase, despite Ankara's efforts to increase foreign investment to boost its economy amid economic turmoil.”

In the dispute, the top appeals court has asserted that the Constitutional Court's ruling for the release of Atalay was unconstitutional. The next stage in resolving the unprecedented row is difficult to predict.

Seemingly backing the Court of Cassation, Erdogan told reporters: "Unfortunately, the Constitutional Court has made many mistakes in a row at this point, which seriously saddens us."

Turkey's bar association and the CHP denounced the appeals court move as an "attempted coup". Hundreds, many of them lawyers in legal robes, on November 10 chanted "justice" on the capital's streets as they demonstrated.

The demonstrators marched more than 10 kilometres from Ankara courthouse to Ahlatlibel district. It is there that the Constitutional Court and the Court of Cassation sit side by side.

In a statement following the protest, the Court of Cassation accused the Constitutional Court of dragging the legal system into chaos with its rulings on individual applications.

"The Court of Cassation is ready to provide necessary support for works on legal and constitutional [amendments] in order to eliminate the problems arisen by the implementation of individual applications," it said.

The crisis showed that Erdogan wants “more control over what happens in Turkey, including a judicial system that does what he wants, such as prosecuting and imprisoning his critics and opponents”, Istanbul-based political analyst Gareth Jenkins was quoted as saying by Reuters.

“His preference is to do things according to the constitution. That is why he has amended the current constitution in 2010 and 2017 and is now talking about a completely new one,” he added.

"The Court of Cassation's backlash ... is an open and combative attack against the Constitutional Court," Bertil Oder, professor of constitutional law at Koc University, was reported as saying by the news service, adding: "Such criminalisation of constitutional judges ... furthers the degradation of the rule of law in Turkey".

Atalay, 47, was sentenced to 18 years in prison last year. He was convicted of attempting to overthrow the Erdogan administration by organising the nationwide “Gezi Park” protests in 2013, along with Turkish philanthropist Osman Kavala and six others. All the defendants denied the charges. They said the protests developed spontaneously.