Turkey detained at least a dozen parliamentarians from the pro-Kurdish Peoples' Democratic Party (HDP) on Friday, threatening to plunge the country into further instability and remove one of the last checks on President Recep Tayyip Erdogan's power.

HDP co-chairs Selahattin Demirtas and Figen Yuksekdag (pictured) were among those arrested and placed in custody pending trial. Prosecutors said the arrests were in response to the lawmakers refusing a subpoena to testify over alleged support for terrorism.

The government accuses the HDP of being the legal front for the outlawed Kurdistan Workers' Party (PKK), which has waged a more than three-decade long insurgency for greater Kurdish rights and autonomy.

The HDP is the third largest party with 59 seats in the 550 seat Turkish parliament.

 

Parliamentarians enjoy immunity but in May this was revoked for any members subject to investigation, a move hitting 138 lawmakers, mostly from the opposition. This paved the way for the arrest and prosecution of HDP members. In September, more than two dozen elected Kurdish mayors alleged to have ties with the PKK were replaced with pro-government administrators.

The arrests and broader crackdown threaten to send Turkey careening down a further spiral of violence as politics is removed from the table, voters are disenfranchised and the PKK's message that the gun prevails over the ballot box gains traction.  The government, in turn, believes it can defeat the PKK militarily, and the Kurdish movement politically.

"The government's official policy, which they believe will succeed, is to defeat terrorism by killing PKK terrorists one by one," academic and Kurdish expert Dogu Ergil told DW. "Arresting parliamentarians means nothing is expected from politics."

Since the failed coup attempt this July, Erdogan has used state of emergency powers to purge the military, bureaucracy and media of alleged followers of the Islamic preacher Fethullah Gulen, who the government blames for orchestrating the coup. More than 100,000 people have been dismissed or suspended for suspected Gulenist ties. The purge has since morphed into a broader assault on all opposition, even those that were traditional rivals of the Gulenists, a former ally of Erdogan.

Kurds as a barrier to Erdogan's presidential system

Since moving from prime minister to president, Erdogan and his Justice and Development Party (AKP) have pushed for rewriting the constitution to turn Turkey into a presidential system. 

The government's argument is that Erdogan has already turned the presidency into an executive position, which is constitutionally a largely ceremonial post, and the de facto situation should become de jure.

The government plans to put forward measures for the new constitution. In order to change the constitution with a referendum the AKP needs 330 votes, but currently has only 317 seats. In order to change the constitution without a referendum two-thirds support, 364 votes are needed for straight parliamentary approval.

The AKP appears to have made an alliance with at least part of the ultra-nationalist Nationalist Movement Party (MHP), which is stridently anti-Kurdish and has recently experienced internal divisions.  The MHP has 40 seats, and a fraction of those could bring the AKP above the 330 seats needed to bring the constitution to a referendum, but short of the 364 need for straight parliamentary approval.

However, if the HDP were closed down, parliamentarians convicted or the party chooses to withdraw from parliament, then those seats would go up for a by-election (or possibly handed to the ruling party), giving the AKP a chance to pick up more seats.

Ayhan Bilgen, a HDP parliamentarian and party spokesman, told DW the arrests are a political move to pave the way for a presidential system.

"This is an attack to neutralize the HDP and to push the country towards a presidential system at the cost of a civil war," Bilgen said.

The Kurdish movement remains one of the last bulwarks against Erdogan's goal to cement power. Indeed, led by the charismatic Demirtas, the HDP for the first time passed the 10-percent electoral threshold in the June 2015 national elections with 13 percent of the vote. 

That stripped the AKP of a majority in parliament for the first time since 2002. Unable or unwilling to form a government, the AKP called for new elections in November that brought it a majority. The HDP's support dipped but stayed above the 10-percent mark. This threshold is the highest in the world, double Germany's 5-percent hurdle.

The inter-electoral period saw a two-year peace process and ceasefire between the PKK and Turkish state break down in July 2015, shattering hopes for a political solution and opening one of the deadliest chapters in the conflict. The HDP blamed the government for reigniting the conflict in order boost the Turkish nationalist vote and peel away those Kurds who only marginally supported the HDP.  The government blamed the PKK for the peace process breakdown.

Nearly 2,000 people have been killed and tens of thousands displaced in near daily fighting since last July.

Turkey concerned over Syrian Kurds

The broader assault on the Kurdish movement coincides with events in Syria and Iraq casting a long shadow over Turkey. Indeed, the breakdown of peace talks was indirectly the result of a July 2015 "Islamic State" terror bombing that killed more than 30 leftists and Kurds on a humanitarian mission to Kobane, the Syrian Kurdish border town that became a symbol of Kurdish resistance across the Middle East.

Turkey has looked on with concern as the Syrian Kurds, led by the PKK-affiliated Democratic Union Party and its armed wing, the YPG, have carved out autonomous zones along the border. The Kurds have been boosted by US backing of the Syrian Democratic Forces (SDF), a joint Arab and Kurdish force dominated by the YPG, to fight IS on the ground in Syria. 

Turkey fears Syrian Kurdish gains will embolden its own Kurdish population, strengthen the PKK, and lead to the ethnic and sectarian breakup of Syria.  Seeking to prevent this development, Turkey has intervened militarily in northern Syria to clear IS forces from its border, establish a safe zone and prevent further YPG expansion.

Deutsche Welle journalist Seda Bilen contributed to this report.