The European Court of Human Rights ruled on Tuesday that Russian dissident Alexei Navalny’s conviction for fraud and money laundering “was based on an unforeseeable application of criminal law and that the proceedings were arbitrary and unfair.”

“The Court considered that the [Russian] domestic court’s decisions had been arbitrary and manifestly unreasonable,” the ruling stated. The conviction “undermined the fairness of the criminal proceedings in such a fundamental way that it had rendered other criminal procedure guarantees irrelevant.”

The court was commenting on a five-year suspended sentence that Navalny had received earlier this year that bars him from running for public office, jeopardizing his plans to run in Russia’s presidential election scheduled for March. Navalny claims the charges are politically motivated.

Navalny was jailed for the third time after he was sentenced to 20 days for violating public assembly laws earlier this month.

He gained popularity after organizing anti-corruption rallies against the government, and running unsuccessfully in Moscow’s mayoral election in 2013.