SEOUL - South Korean President Yoon Suk Yeol is facing the threat of impeachment, with opposition lawmakers accusing him of violating his constitutional duty and committing a crime akin to treason when he declared martial law on Dec 3.

Mr Yoon lifted the martial law declaration before dawn on Dec 4, just hours after opposition-controlled parliament rejected his attempt to ban political activity and censor the media.

Below are details of the presidential impeachment process and past presidents who were impeached.

What is the law?

The Constitution provides for Parliament to bring an impeachment motion against the president or other high-ranking public officials if they are believed to "have violated the Constitution or any law in the performance of official duties".

The presidential impeachment motion needs a two-thirds majority vote by the members of the single-chamber Parliament to pass. A simple majority is needed to impeach other officials.

The Constitutional Court conducts a trial to either confirm or reject the impeachment motion, hearing evidence from parliament to determine whether the president violated the law.

Does the opposition have the votes?

Parliament is currently controlled by the main opposition Democratic Party, which has vowed to impeach Mr Yoon. The party and other smaller parties have 192 seats, just short of the 200 required to impeach the president.

Some members of Mr Yoon's ruling People Power Party have strongly objected to his martial law declaration, but it was not clear if or h...