Turkey's parliament has approved a government-sponsored bill that would lift lawmakers’ immunity from prosecution, in a move that paves the way for the trial of members of the pro-Kurdish party HDP on terror-related charges.

In the second and final vote on May 20, 376 lawmakers in the 550-seat parliament backed the bill, securing a high enough level of support for direct change to the constitution without the need to hold a referendum, CNN Turk reports.

Currently 138 MPs are facing criminal investigations, but the HDP says the bill is directly targeting its 50 deputies. President Recep Tayyip Erdogan has repeatedly called for the prosecution of HDP lawmakers, accusing them of being an extension of the outlawed Kurdistan Workers’ Party (PKK). 

The bill also targets 51 lawmakers from the main opposition Republican People's Party (CHP) to allow prosecutions of them on a range of charges, including insulting Erdogan.

Critics, including CHP and HDP lawmakers, accuse the ruling party of trying to put more pressure on opponents. Given the government’s control over the judiciary, the accused lawmakers could face the threat of arbitrary detentions and may not receive a fair trial, they claim.

“This [lifting immunity] boosts the chances of Erdogan getting his executive presidency, as we are likely to see the mass removal of many of these deputies, by-elections, particularly for HDP deputies, which the ruling AKP will hope to win to get either the three fifths or two thirds majority to push forward with constitutional reform,” Tim Ash at Nomura said in an emailed comment on May 20. It reduces the chances of early parliamentary elections, but we may still see a referendum on the executive presidency, he adds.

Critics believe the AKP’s move to lift the immunity of lawmakers is part of Erdogan’s larger plan to tighten his grip on power. The HDP is the largest political grouping in parliament and if all its deputies are pushed out of parliament somehow, Turkey will need to call by-elections to fill the vacancies. According to the constitution: “in cases where the number of vacant seats reaches 5 percent of the total number of seats (550), by-elections shall be held within three months”.

Erdogan likely hopes his ruling party will increase its seats in parliament through by-elections and thus secure a stronger support to push for constitutional changes that would give him more executive powers. Though it regained the parliamentary majority in the November elections with 317 seats, the AKP failed to secure enough seats – 330 in the 550-seat parliament – to allow it to hold a referendum on the new constitution. If it had won 367 seats it would have been able to re-write the constitution by itself without a referendum.

A survey by polling company Gezici found in April that support for the HDP stands at 7.3%. The Kurdish party won 10.8% of the votes in the November elections, down from the 13.1% backing it secured in the June snap elections.

HDP claims the bill aims at wiping out its parliamentary presence. The HDP has 59 seats in parliament and 50 of its deputies are facing investigations. HDP lawmakers will not immediately lose their seats in parliament even if their immunity is lifted. 

If HDP MPs are tried and found guilty for terror-related charges and consequently lose their seats, this may provoke and even radicalise the country’s Kurdish population and Turkey may see further escalation in the violence that has engulfed the south-eastern provinces since last summer, when a two-year ceasefire between the state and the PKK collapsed. HDP’s co-chair Selahattin Demirtas said earlier this month that HDP lawmakers would defy calls to appear before courts if they face charges, signalling serious tensions in the period ahead.

The outlawed PKK launched its insurgency in 1984. More than 40,000 people have been killed in the Kurdish conflict. Erdogan refuses any negotiations with the PKK, vowing to eliminate all PKK militants.  “It raises big issues for Turkey's Western partners, particularly the US and Germany, as the HDP had been seen (at least up to last year's parliamentary elections) as a moderate and representative voice of Kurdish voters/interests,” Ash said. Some Western politicians will be very nervous/unhappy that a key Rubicon will have been crossed in terms of Turkish democracy, according to the Nomura analyst.

In a sign of how deeply polarised the country is, lawmakers from CHP walked out of the chamber on Friday ahead of the vote in protest at recent remarks by Parliament Speaker Ismail Kahraman, from the AKP, who called for the adoption of a religious constitution. “Turkey is secular and will remain secular," CHP deputies chanted as they left the national assembly. Later, the senior AKP official said the secularism, one of the main founding principles of the republic, would not be abandoned.

The increasing polarisation of the domestic political debate in Turkey is raising concerns in Germany and Chancellor Angela Merkel will broach this topic with Erdogan at a meeting on May 23, a government spokesman said on Friday, according to Reuters. European leaders are also increasingly concerned that the departure of Prime Minister Ahmet Davutoglu is jeopardising the implementation of a key migrant deal between the EU and Turkey to stem to inflow of refugees. Merkel and Davutoglu were the main architects of the migrant accord.

Erdogan, who is seen as more sceptical towards Brussels than outgoing PM Davutoglu, has recently taken a tougher line on the EU, rejecting demands by the EU to change the country’s anti-terror laws, one of the key conditions Turkey must meet for the EU to relax visa requirements for Turkish nationals. He even suggested that Turkey could abandon the agreement. “We'll go our way, you go yours…Go make your agreement with whoever you can”, he rebuked in a recent public speech.