Several high-profile politicians joined the ADC in 2025 - disillusioned by the factional infighting in the once powerful Peoples Democratic Party (PDP).

Among them were Abubakar - who had served as vice-president between 1999 and 2007 when the PDP was in power - and former Senate president David Mark.

As accommodations were made for the line-up of political heavyweights, Mark took over as its interim chairman.

But Nafiu Bala Gombe, a former ADC national deputy chairman, argued before the court that this was not lawful as Mark and others had not been elected at a national convention.

Instead, he said, he himself should have taken over the party's leadership following the resignation of the ADC's former chairman in 2025.

This is not first time the Federal High Court in the capital, Abuja, has ruled on the leadership of the party.

In July, judge Musa Liman said Mark had been chosen in accordance with the country's laws and the party's constitution - in a case brought by another former ADC member.

Abubakar said the latest case raised serious legal concerns: "Why, after that judgment, was another case filed to reopen the same dispute?"

In a statement, the ADC added that Thursday's judgement by Justice Peter Lifu was aimed at stifling the opposition momentum and "was a calculated attempt to weaken the ADC and frustrate" Abubakar's candidacy.