How many Americans today would have any idea what you were talking about if you mentioned the 38th parallel? How many would stare blankly if you mentioned Syngman Rhee? How many would be able to tell you what this photo depicts? 

It is a cliche that the so-called police action in Korea from 1950 to 1952 is America’s “forgotten war.” But, like most cliches, there is a lot of truth to it. American ignorance about the Korean War is a shame, and not only because it devalues the sacrifices of those who fought in it. With North Korea’s nuclear arsenal now threatening the U.S. mainland (not to mention Hawaii, Japan and the folks on the southern end of the peninsula), and President Donald Trump and Kim Jong Un set to meet again next month, a little historical perspective might be helpful. 

One person who agrees with me is Hampton Sides, the best-selling writer of historical nonfiction including “Ghost Soldiers,” a page-turner about the secret mission to rescue U.S. survivors of the Bataan Death March in World War II. Sides’s latest book, “On Desperate Ground,” recounts another little-known chapter in American military history: the savage 1950 battle at the Chosin Reservoir, in which 20,000 Marines fought off more than 300,000 Chinese troops to escape a trap that might have ended the war in defeat.