ISTANBUL, Turkey — Turkey’s ruling party reclaimed its parliamentary majority Sunday in an election that represented a surprising turnaround for the Islamist-rooted movement and its pugnacious leader, President Recep Tayyip Erdogan.

Sunday’s vote was a redo of a parliamentary election in June. That vote saw Erdogan’s Justice and Development Party, or AKP, stripped of its parliamentary majority for the first time in 13 years. Its inability to cobble together a coalition led to the vote on Sunday.

Since June, Turkey has been beset by violence, including a twin suicide bombing in the capital, Ankara, that left more than 100 people dead and a rekindled Kurdish insurgency in the country’s southeast. Many voters saw the ruling party as best equipped to deal with the crisis.

“Turkey is in the middle of a storm,” said Ilker Sariaydin, a civil engineer and AKP supporter, speaking outside a polling station in Istanbul’s Erenkoy district. “Erdogan is like the captain of a ship, steering us to shore and to safety.”

Results published by the semi-official Anadolu news agency showed the AKP garnering 49.4% of the vote, a 10-point increase compared with June’s results. That is enough to allow the party to govern alone, but not enough to make changes that Erdogan wants in the constitution.

About 85% of eligible voters turned out for the vote, and long lines snaked out of many of the 175,000 polling stations across the country.

In the lead-up to Sunday’s vote, Erdogan and the AKP cast it as a choice between stability and chaos, a message that resonated with many Turks facing a slowing economy and spillover from the wars in neighboring Iraq and Syria.

A large crowd of party faithful gathered outside the AKP’s headquarters in Ankara on Sunday evening, waving flags, chanting “God is Great” and denouncing Israel — all reflections of Erdogan’s nationalist, pan-Muslim appeal. The scenes were a striking turnaround from June, when Prime Minister Ahmet Davutoglu gave a dejected speech to a tiny crowd as it became apparent that the Islamists had been dealt a striking setback.

“The results are stunning. The AKP managed to erase its losses from June 7 and reclaim elements of its base that it had lost,” said Aaron Stein, a Turkey watcher and associate fellow with the Royal United Services Institute. “In particular, they were able to win nationalist votes and pious Kurds who had [previously] defected from the party.”

The AKP’s campaign strategy centered on emphasizing its nationalist tendencies, seeking to lure voters away from the far-right Nationalist Action Party. In recent months, for instance, Erdogan renewed the country’s war with the outlawed Kurdistan Workers’ Party, or PKK, and recruited the son of the founder of the ultra-nationalist Gray Wolves movement into the AKP.

The Nationalist Action Party slid from 16% of the vote in June to just under 12% on Sunday. Many nationalists had been angry that the party’s leader, Demet Bahceli, refused to enter into a coalition after the June vote, paving the way for Sunday’s election.

“People are furious with Bahceli,” said Orcun Behram, a supporter of a Kurdish party. “Because of him, we missed our only chance to clean out the government and stop Turkey becoming more authoritarian. Now, there is no going back.”

Sunday’s vote is certain to embolden Erdogan, who seeks to reshape the Turkish republic. With the AKP’s rule assured, he can accelerate his plans for a “New Turkey.”

Sunday’s results were not an unalloyed triumph for the ruling party. The pro-Kurdish Peoples’ Democratic Party once again — albeit narrowly — passed the country’s 10% threshold for representation in parliament, scuttling Erdogan’s goals of formalizing a de facto presidential system through constitutional changes.

For Erdogan’s opponents, Sunday’s results were particularly bitter and raised fears that the country’s authoritarian slide may accelerate.

“Sadness, disappointment, hatred, anger. I feel desperate,” said Cansu Albayrak, who volunteered with the civil initiative Vote and Beyond to keep Sunday’s vote clean. “I really need someone to explain this to me. Why does 50% of this country not want justice, peace, law and human rights? But, instead, oppression, police violence and hatred everywhere.”