France's highest court decides Tuesday whether wiretaps of phone conversations between Nicolas Sarkozy and his main lawyer are legal, a much-anticipated ruling that could pave the way for a corruption trial against the former president.

Sarkozy is expected to seek the conservative nomination to run for president again next year, but the possibility of a trial could hamper his bid.

The opposition leader is under preliminary charges of corruption and influence-peddling based on information gleaned from judicial phone taps in 2013-2014. His lawyers have argued the wiretapping was carried out in breach of lawyer-client privilege.

If the top court upholds the legality of most of the phone taps and ensuing evidence, as the prosecutor has asked them to do, the preliminary charges will stand against Sarkozy.