The deadly politics behind Turkey's worst ever terrorist attack

The twin bomb blasts that tore through a peace rally in the Turkish capital on Saturday, killing at least 86 people, are being described as the deadliest attack in the history of modern Turkey.

The bombings targeted a gathering organized in part by the Peoples' Democratic Party (HDP), one of the country's leading opposition parties, just weeks before a new round of national elections are scheduled to be held.

It's unclear at present who is behind the suspected suicide attack, but the bloodshed is bound to exacerbate tensions in Turkey, which has experienced a deepening and deadly polarization since elections in June failed to produce a stable government.

The HDP is a leftist, largely Kurdish party that emerged only in recent years. In June, it scored a stunning electoral victory, winning more than 10 percent of the vote -- in Turkish politics the threshold a party needs to cross to gain a bloc of seats in parliament. The HDP's success was a huge blow to the ruling Justice and Development Party, or AKP, of President Recep Tayyip Erdogan, which lost its parliamentary majority for the first time since 2002.

The HDP was buoyed by anti-Erdogan sentiment across the nation, as well as widespread support from Turkey's Kurds, a minority ethnic group that represents roughly a fifth of the country's population but whose votes have traditionally been split.

The HDP's success was considered a landmark moment. Some HDP politicians who entered parliament have relatives in the PKK, a Kurdish separatist guerrilla organization that is deemed a terrorist group by both Ankara and Washington. The Kurdish insurgency, which has blown hot and cold for more than 30 years, has claimed some 40,000 lives. Yet here were the Kurdish nationalists galvanizing non-Kurdish voters and entering the Turkish political mainstream after decades of marginalization.

Three months later, and the HDP's euphoria in June seems an eternity ago.

None of Turkey's four main political parties, including the AKP and the HDP, were able to form a coalition government. Meanwhile, long-running animosities exploded in Turkey's largely Kurdish southeast, with the PKK ending a fragile cease-fire and resuming attacks on Turkish security forces. Turkey embarked on a concerted counterinsurgency campaign, placing towns under curfew and conducting airstrikes against PKK mountain redoubts, including camps across the border in northern Iraq.

Hundreds died over the summer in what's been a low-level civil war next-door to Syria. The HDP has championed the cause of peace and criticized the Turkish government for its heavy-handedness. The rally in Ankara reflected their efforts to call for calm. Yet the party's opponents, including Erdogan, still cast the group as the sheep's clothing masking the wolf that is the PKK.

Critics of Erdogan say the Turkish president and his ruling party have stoked the tensions for political gain, hoping that deepening anti-Kurdish sentiment would undermine the HDP in new elections. It's a charge angrily dismissed by the Turkish government. Whatever the case, current surveys suggest the HDP will retain its level of support, and perhaps gain more in the Nov. 1 elections.

The question then is: What will Erdogan do? The June election was seen as a referendum on his ambitions for further power. Erdogan, who had served as prime minister from 2003 to 2014, sought a parliamentary super-majority so he could change Turkey's constitution and usher in a presidential system in which his office would be endowed with greater executive powers.

The AKP's worst showing in more than a decade left Erdogan's plans in tatters. Yet he has not retreated into the ceremonial, non-partisan role usually reserved for the Turkish presidency under the current system, in which the country's prime minister, Ahmet Davutoglu, should technically be its most powerful political figure.

Over the past decade, Erdogan has become the most influential Turkish politician since the republic's founder, Mustafa Kemal Ataturk. He brought to heel the country's long-meddling military, ushered in economic reforms that lifted up a new Turkish middle class and has steadily chipped away at Ataturk's secularist legacy, embracing instead a religious nationalism popular among a wide swath of Sunni Muslim voters outside Turkey's major cities on its western coast.

In recent years, Erdogan has earned a reputation as a would-be autocrat, playing a majoritarian game to consolidate his own base and hold onto power. Some dissenting voices in the media have been muffled or intimidated. Liberals and others who once supported Erdogan's reforms now fear attack from elements of the state.

There's a heated, volatile political climate, where divisions are pronounced and prospects for reconciliation dim. Last month, the offices of the Hurriyet newspaper, one of Turkey's biggest dailies, were attacked by nationalist mobs for the paper's supposedly anti-Erdogan coverage.

"As spectators of Turkish politics, we are currently watching an end-to-end pileup in slow motion," writes Burak Kadercan of the United States Naval War College.

The current polarization is also affected by the disastrous conflict in Syria, which has entered its fifth year and impelled as many as 2 million Syrian refugees to flee to Turkey. The successes of Syrian Kurdish factions, who have carved out a de facto rump state along Turkey's border, have both alarmed Ankara and spurred Kurdish nationalism within Turkey.

As WorldViews noted earlier, hundreds of Turkish Kurds have joined the Syrian Kurdish units fighting the Islamic State and other factions in Syria. Leftists and other HDP supporters were among the dozens killed in July by a suspected jihadist suicide bombing in Suruc, a Turkish border town adjacent to the Syrian Kurdish bastion of Kobane.

With each new incident of violence, the likelihood of further escalation has grown. Before the Ankara bombing, the PKK offered a unilateral cease-fire ahead of the elections. Now there's a chance some of the PKK's more rogue or radical wings could engage in further destabilizing attacks.

The onus falls on Erdogan to bring Turkey back from the brink. The president may have played a key role in the country's polarization, writes Washington-based analyst Soner Cagaptay, but "it's ultimately up to him to tamp down tensions before they explode." After Saturday's carnage, one fears how much worse it can get.