South Korean President Yoon Suk Yeol declared martial law overnight, then rescinded it. This was after mass violent protests on the streets, as outraged citizens clashed with heavily armed police. The Opposition leader Lee Jae-myung, called Yoon's announcement "illegal and unconstitutional," which it was.
According to South Korea's Constitution the president can only declare martial law when it is necessary to cope with a military threat or to maintain public safety and order by mobilising military forces. When the president declares martial law, the president must notify the National Assembly of the decision which can then take a vote on whether martial law should continue. This did occur, with a resolution to lift martial law being made.
The National Assembly, with 190 of its 300 members present, had already passed a resolution demanding the martial law be lifted. South Korea's military announced that martial law will remain in place until it is lifted by the president. The defence ministry stated: "We will maintain the martial law command until the president lifts the martial law."
So, a direct violation of the constitution occurred, if only for six hours, but still a violation. This shows where the interests of the police and military, those with the guns lie, and it is not with the democratic process. The same would be seen other jurisdictions and was seen during Covid, where basic civil and medical rights were crushed, and this was backed by the police who could have refused orders.