As is generally known, the DPRK and South Korea retain a formal "state of war" between themselves, since the South refused to sign the peace treaty ending the war. What if it did in the 70's-80's, how much opposition would there be in the South (presumably among the military and conservative politicians) and what political and international effects would it have?
I could see the continued presence of US troops in the South being a bigger issue, for example.