"I declare martial law to protect the free Republic of Korea from the threat of North Korean communist forces, to eradicate the despicable pro-North Korean anti-state forces that are plundering the freedom and happiness of our people, and to protect the free constitutional order," Mr Yoon said.
They are totally free to vote for anyone* they want!
*As long as they are anti-China, anti-DPRK, and pro-US.