Duck Soup is the most famous and arguably the best of all the Marx Bros.' movies, though audiences at the time of its release were confused and disappointed. One reason for this, I think, is that the movie is really just a series of comedy sketches strung together by the barest thread of a plot. But the comedy sketches are unforgettable, and the audience is treated to one unforgettable, side-splitting scenario after another: the inauguration of Rufus T. Firefly ("Pop Goes The Weasel" ), the spies, the book seller, the mirror scene (imitated countless times over the years), and "Freedonia's Going To War!" Groucho said many of his best lines here; Chico is the straight man who changes sides in the war at the drop of a hat; and Harpo is bursting with energy (and lechery). Margaret Dumont plays the straight lady to Groucho's insults and affections (and it's said that in real life, she didn't understand half of the things being said about her!). This was Zeppo's last movie with the other Brothers, as their cartoony antics continually overshadowed him. Much has been made of the political satire present in this movie; and indeed, in these crazy times after the events of September 11, 2001, the antics of a number of the people in power (on both sides of this conflict) can be compared to the antics of Rufus T. Firefly.
Viewers who watch this movie expecting an actual plot will be disappointed, which may be the reason why the it was a box-office flop. Newcomers should take this movie in the way they take a Monty Python movie, as a series of comedy sketches. It's sad to have to invoke the name of Monty Python when praising this all-time comedy classic, but the truth is that these days, far more people have seen Monty Python and the Holy Grail than any of the great Marx Bros. movies.