By "previously" we could be talking 1953 here.
Yep, my first thought as well.
"52,000 US military casualties"?? Horse manure.
By 1953 the Korean War was over, there were 55,000 deaths and many, many more casualties, so this is a recent estimate by a fearful leadership with no vision, no effective strategies (such as a massive and prolonged bombing campaign). Anyway, it's a red herring in an effort to save face for the White House, because we don't need to attack Poingyang, we need to drop a few tactical nukes or huge conventional bombs on their nuclear weapons sites. There is no need to take on the entire country.