South Korea's Constitutional Court has begun considering the unprecedented impeachment of President Roh Moo-hyun.
President Roh has been suspended while judges debate his fate
Last week the opposition-controlled parliament voted to unseat Mr Roh - just one year into his five-year term in office - for breaking election law.
The court has 180 days to rule on whether the move was constitutional. The president has been suspended until a decision is reached.
Acting President Goh Kun has urged the judges to rule as quickly as possible.
The impeachment was initiated by South Korea's conservative opposition.
WHAT HAPPENS NEXT?
President Roh's powers suspended
Case decided by Constitutional Court, could take six months
PM Goh Kun becomes acting head of state
15 April National Assembly elections to go ahead
They will need the support of at least six of the court's nine judges for the impeachment to go forward.
If they uphold the impeachment decision, Mr Roh will be stripped of his office and a new presidential election held within 60 days of the court's verdict.
The court's first meeting was held to decide on procedure for the hearings.
It arranged to hold the first public hearing on 30 March. It is not clear whether Mr Roh himself will attend but he must be represented there.
Meanwhile the government has warned North Korea to stay out of its internal affairs.
It said relations could be damaged if the north continued to make unfounded comments about the impeachment.
North Korea said it had proved the political backwardness of the South and accused the US of involvement.
North Korean officials failed to turn up for talks on economic co-operation this week citing political instability as the reason.
Opposition MPs will argue that the president should be removed for illegally backing the minority Uri Party in upcoming elections, and also accuse him of corruption and incompetence.
But the president's legal team will say the charges are politically motivated.
Some of the president's supporters are describing the vote in the national assembly as a coup d'etat.
Polls show 70% believe the main charge of violating electoral law is not serious enough to warrant such a move.
At the weekend tens of thousands joined demonstrations across the country in support of Mr Roh.
The court has promised to work as quickly as possible, but a verdict is not expected before national assembly elections in the middle of April.