The difference was stark.
In Ankara, the Turkish capital, President Recep Tayyip Erdogan hosted NATO leaders in his palace and basked in the praise of President Trump.
In Istanbul, a politician who planned to challenge Mr. Erdogan for the presidency sought to defend himself in court before being returned to his jail cell.
“This is a political case — entirely,” the politician, Ekrem Imamoglu, told a panel of judges. “This is the murder of the law.”
Since 2019, Mr. Imamoglu has beat candidates backed by Mr. Erdogan three times to become and remain the mayor of Istanbul, Turkey’s largest city.
That made him a rising star in Turkey’s political opposition, and he announced his intention to run in the country’s next presidential election, scheduled for 2028. Some polls suggested he could beat Mr. Erdogan in a head-to-head contest.
Mr. Imamoglu was arrested last year and later accused by prosecutors of enriching himself and funding his political ambitions through a criminal organization inside city hall. He was removed as mayor and jailed pending trial. Prosecutors are seeking to send him to prison for more than 2,000 years.
Mr. Imamoglu has denied all wrongdoing. Rights groups and his supporters have dismissed the charges as political moves by Mr. Erdogan’s government to eliminate a political rival.
The government has repeatedly insisted that its legal system is free from political interference, and Mr. Erdogan has spoken of Mr. Imamoglu as the head of a vast criminal conspiracy.
The trial of Mr. Imamoglu and more than 400 other defendants facing similar charges, opened earlier this year. On Wednesday, when global attention was focused on the NATO summit in Ankara, Mr. Imamoglu challenged a decision by the judges that he be given only through Thursday to make his defense.
“This is a grave breach of rights and you are harming the Turkish judiciary,” he said.
The judges rejected his request for more time.
Despite waves of arrests of opposition figures and a crackdown on dissent in the run-up to the summit, NATO officials did not publicly address what some see privately as rising autocracy in Turkey. Rights groups say Turkey’s increased importance to NATO allies has silenced criticism of Mr. Erdogan’s domestic governance.
In the courtroom, the head judge accused Mr. Imamoglu of disrupting the court.
“I am not going to defend myself,” Mr. Imamoglu said, adding that he should judge those who he said had wrongly accused him.
“You cannot judge,” the chief judge replied. “You are here to be judged.”
He ordered Mr. Imamoglu’s removal from the courtroom.
The former mayor’s supporters in the gallery booed and chanted, “President Imamoglu!” as security officers led him from the room.
The court then decided that Mr. Imamoglu had exercised his right to remain silent and chosen not to offer a defense.
