A man who stabbed South Korea’s opposition leader in the neck earlier this year was sentenced to 15 years in prison on Friday, court officials said.

The knife-wielding man attacked Lee Jae-myung, head of the liberal Democratic Party, South Korea’s biggest political party, in January after approaching him asking for his autograph at an event in the southeastern city of Busan. After being detained by police, he told investigators that he wanted to kill Lee to prevent him from becoming South Korea’s president.

The Busan District Court said the man was handed the prison term after being found guilty for an attempted murder and a violation of an election law.

The court said that both the man and prosecutors have one week to appeal.

The attack happened ahead of the country’s crucial parliamentary elections in April, which ended with Lee’s Democratic Party and other opposition parties winning a massive victory against President Yoon Suk Yeol’s conservative governing party.