I'm re-reading the Cambridge Companion to Brecht, about the work of German director and playwright Bertolt Brecht, co-creator of The Threepenny Opera, and also the primary target of Urinetown's stylistic satire. Here are a few choice quotes about Brecht's political theatre that relate to the style and theatrical devices of Urinetown...
Eric Bentley on Brecht's theory of "epic theatre" -- The new narrative content signaled by the term "epic" was to be communicated in a dialectical, non-illusionist and nonlinear manner, declaring its own artifice as it hoped also to reveal the workings of ideology. "Alienating an event or character," wrote Brecht, "means first of all stripping the event of its self-evident, familiar, obvious quality and creating a sense of astonishment and curiosity about them." The direct and indirect use of a narrator, the conspicuous use of songs, masks, placards and images set in a montaged narrative sequence would help maintain this level of wonder and alert self-criticism. Beyond this, however, the repertoire of estranging effects would aim to produce a double perspective on events and actions so as at once to show their present contradictory nature and their historical cause or social motivation.
Bentley on Brecht's play The Mother -- The set was "quoting" an environment rather than representing it; there was extensive use of projections and scene titles; the small chorus, in its songs to the audience, commented on the fable and/or the actions shown on stage; there was an enchanting ease and, yes, elegance with which even the most serious scenes were performed.
And Brecht on Singing -- "Nothing is more revolting than when an actor pretends not to notice that he has left the level of plain speech and started to sing."
Long Live the Musical!