Taiwan's top court on Thursday (Jan 3) ordered a new trial of former president Ma Ying-jeou, revoking his conviction in a political leaks case, one of a raft of lawsuits brought against him since he stepped down in 2016.
Ma was sentenced to four months in prison last year by the high court for violating the communication security and surveillance act, overturning a previous not guilty verdict from a lower court.
Ma's Beijing-friendly Kuomintang (KMT) party held power from 2008 to 2016, before it was trounced by Ms Tsai Ing-wen's Democratic Progressive Party (DPP).
While still in office Ma was protected by political immunity.
But since he stepped down as leader in May 2016, the 68-year-old has been hit with a string of corruption and other allegations.
Last year's high court ruling was his first conviction, which Ma appealed against.
"The original judgment did not state and clarify the essential facts about whether Ma had committed the crime," the supreme court said in its statement revoking the original ruling and ordering a retrial.
The high court had found Ma guilty of breaching the personal data protection act and of "using his presidential power not for executing presidential legal duties".
It said Ma had attempted to damage the "character and rights" of opposition lawmaker Ker Chien-ming when he leaked confidential information about an ongoing probe associated with Mr Ker.
The probe revolved around information gained from surveillance on Mr Ker which implicated the then parliamentary Speaker, a rival of Ma, in influence peddling.
Investigators had been accused of tapping Mr Ker's phone to acquire the information.
The leaks controversy sparked a political storm in 2013 and saw two top officials resign, while thousands of protesters took to the streets to demand Ma step down.
The DPP, then in opposition, compared the probe to the Watergate scandal in the United States.