"I like the island Manhattan! Smoke on your pipe and put that in!"

No song from "West Side Story" has become as iconic as the one seen above.  "America" is yet another example of Bernstein experimenting with rhythm.  Meter changes were not unheard of in musical theatre.  Granted, old Tin Pan Alley writers tended to stick to 4/4, 3/4, or 6/8 and to an AABA song form but composers like Richard Rodgers (especially in his work with Oscar Hammerstein II) stated to use meter changes a bit in the 40's.  However Bernstein went where no other musical theatre composer had before.  The song "America" had (as you can see in the image above) a consistently changing meter every other measure from 6/8 to 3/4.  Although the value of the eighth note stays the same the accents change each measure.

What this meter change accomplishes is motion.  The 3/4 measure propels the song forward and almost feels as if the song is running for a measure and then stays in place for the 6/8 measure.  Some say that the meter change is a hemiola, which is technically inaccurate because they are not happening simultaneously but instead happening one after the other, but it is also written in the Habanera dance style.  The following is a clip of the production number "America" from the recent Broadway revival of "West Side Story".