There are theoretically two different types of peace agreement: a broad and comprehensive peace agreement, and a narrow and limited peace agreement. In the real world, the latter, small-package peace agreement is the only practical option under which an armistice can be replaced by peace and peacetime international law can start to apply, but a substantial level of armed force will remain on both sides. If a peace agreement were to be concluded, the international mechanisms for maintaining the Korean armistice would disappear. The UN resolutions adopted at the time of the Korean War would become void. The United Nations Command would be decommissioned. The Military Armistice Commission and the Neutral Nations Supervisory Commission would cease to exist. At the same time, necessary security mechanisms would stay, however. The US-ROK alliance would remain; US forces would stay; and the United States would continue to provide a nuclear umbrella to South Korea. The most difficult issue in negotiating a peace agreement is the issue of replacing the Northern Limit Line (NLL) with a new maritime borderline. The most likely candidate for the new line is the one based on the 1994 United Nations Convention on the Law of the Sea. However, the new borderline would hamper South Korean fishing activities, and it would be politically difficult for South Korean leaders to give up the NLL.