South Korean police have questioned Prime Minister and Acting President Han Duck-soo as part of an investigation into the short-lived decision this month to impose martial law, an official at his office said on Friday.

For the United States, the turmoil in South Korea is potentially disruptive to its geopolitical agenda in East Asia.

The president faces an accusation of insurrection and, in a first for a sitting leader, the possibility of arrest. Here’s what to know about his political future.