WASHINGTON — When the government of South Korea announced last week that it would begin work on a formal peace treaty with North Korea, to be discussed at a summit meeting on April 27, its so-called Sunshine Policy of engagement gave way to P.T. Barnum-style, a-sucker-born-every-minute diplomacy.

Fighting in the Korean War ended in 1953 with just an armistice, and South Korean officials are calling for a “permanent peace.” But it is not merely unrealistic to hope that Kim Jong-un, the leader of the North, will offer the South real and lasting peace; it is delusional.

If the past is any guide, the North will offer the South unenforceable verbiage. And if the South accepts a phony peace ploy, it will expose itself to more manipulation by the government in Pyongyang — not only in its domestic politics, but potentially also in its alliance with the United States.

Let’s begin with the obvious. A peace treaty between two countries is a legal document that requires one sovereign state to recognize the other sovereign state’s right to exist. (Think Camp David accords of 1978, when Egypt agreed to recognize Israel.) Yet North Korea cannot commit to any such thing with South Korea, not least because the existential objective of its ruling family, the Kims, has been to wipe the state of South Korea off the face of the earth.