origin of 'sad sack' (an inept blundering person)

USA, 1942, Army slang—popularised in the Army weekly ‘Yank’ by ‘The Sad Sack’, a cartoon strip by George Baker, depicting the misfortunes of an inept private

Smiley's People – John Le Carre - bzelbublive.info

RIVERSIDE: George Baker created Sad Sack – Press Enterprise

Sad Sack: A trip down memory lane

Peanuts (Comic Strip) - TV Tropes

Adult Recommendations Ela Area Public Library

Principles of Politics Applicable to All Governments

Sad-sack - Idioms by The Free Dictionary

Calaméo - 2006 2012 Tainted Trials Stolen Justice Series Sjmerury

Who was the most inept Allied commander in World War II? I have read that Field Marshal Montgomery made a lot of mistakes. Are there other commanders who made many mistakes?

Sad Sack - Alchetron, The Free Social Encyclopedia

Daredevil – Now Read This!