ISTANBUL, March 6, 2026 (BSS/AFP) - Turkish opposition challenger Ekrem Imamoglu goes on trial Monday on corruption charges, making it increasingly unlikely he'll contest the next election, analysts say. But his party insists it remains viable despite mounting legal pressure.

Istanbul's jailed mayor, a popular and powerful rival of President Recep Tayyip Erdogan, is due in court for the opening of a sweeping graft case in which prosecutors want him jailed for 2,430 years.

They claim that the 54-year-old ran a sprawling criminal network over which he exerted his influence "like an octopus".

Analysts say Imamoglu, who was thrown in jail a year ago on the day he was named candidate for the main opposition CHP, almost certainly won't be able to run in the next presidential race.

Even if he was to be exonerated of the graft charges, the mayor is facing an even more significant legal obstacle: a lawsuit challenging the validity of his university degree -- a constitutional requirement for presidential candidates.

- 'Zero chance' -

While CHP has not publicly discussed alternatives, political observers expect party leader Ozgur Ozel to emerge as the likely candidate should Imamoglu be barred.

"Imamoglu's chances of coming back to politics before a presidential election are zero," Halil Karaveli, senior fellow at the Central Asia-Caucasus Institute, told AFP.

"Even in the very unlikely case he would be acquitted in this trial, you still have the problem that his university diploma could be revoked which, of course, disqualifies him" from the presidential race, he added.

CHP won a resounding victory in the March 2024 local elections against Erdogan's ruling AKP, cementing its hold on major cities such as Istanbul and Ankara.

Since then however, it has faced a sweeping legal crackdown, and 15 of its mayors are now behind bars.

Senior CHP leader Burhanettin Bulut accused the government of "using the judiciary as a weapon to shape politics in the corridors of the courts" following its 2024 election defeat.

"Many of our municipalities have been subjected to unlawful political operations, and our elected mayors and colleagues have been imprisoned, disregarding the will of the people," he told AFP.

For the CHP, the March 9 trial involving Imamoglu and 407 other defendants was not merely a court date but a "critical milestone for the rule of law and the future of democracy in Turkey", he added.

"For us, this is not just about defending a mayor, but about upholding the voters' will and protecting the rule of law," he said.

"So we will present a robust legal defence while demonstrating steadfast commitment to democratic solidarity."

As the trial opens, CHP is planning to set up a tent encampment in a show of solidarity outside Silivri courthouse, which is attached to the jail where Imamoglu has been held for nearly a year.

Silivri lies 80 kilometres (50 miles) west of Istanbul.

- Ozel as next candidate? -

Human Rights Watch described the trial as "a politically motivated" prosecution that raised "serious fair trial concerns".

"The trial of Mayor Imamoglu follows more than a year of weaponising the criminal justice system against his party and other CHP elected officials while he sits in jail," HRW's Benjamin Ward said in a statement.

"It's hard to avoid the conclusion that prosecutors are trying to remove Imamoglu from politics and discredit his party in ways that undermine democracy."

The most likely scenario being discussed in Ankara's political corridors is an early election in the autumn of 2027, allowing Erdogan to run for another term.

Speaking to AFP, Bulut said there was strong backing within the party for Imamoglu's candidacy.

"However, should any legal or political obstacles arise, we will act with a common mind, embracing the broadest segments of society and determining the name that will garner the strongest support from the nation," he said.

Although he did not say who could run instead, Karaveli suggested Ozel would be the "natural" candidate.

"He has really done a great job of becoming a popular leader," he told AFP.

"I think he has a chance."