It's just harder to create a veneer of the constitutional necessity of such a move when your own highest profile political allies apparently condemn it and pledge to "stop it with the people" instead of queuing up to rubber stamp it and do "this is a small problem with criminal elements in one party which is all resolved now" briefings to confused foreigners wondering who the real government of South Korea is.

Edit: reportedly the National Assembly has actually managed to hold a vote against it. Not sure how or what the constitutional quirks are, but that's probably going to make it considerably less likely the military unites behind the President...