  The propagation of electromagnetic waves in isotropic dielectric media with
local dispersion is studied under the assumption of small but nonvanishing
$\lambda/l$, where $\lambda$ is the wavelength, and $l$ is the characteristic
inhomogeneity scale. It is commonly known that, due to nonzero $\lambda/l$,
such waves can experience polarization-driven bending of ray trajectories and
polarization dynamics that can be interpreted as the precession of the wave
"spin". The present work reports how Lagrangians describing these effects can
be deduced, rather than guessed, within a strictly classical theory. In
addition to the commonly known ray Lagrangian featuring the Berry connection, a
simple alternative Lagrangian is proposed that naturally has a canonical form.
The presented theory captures not only eigenray dynamics but also the dynamics
of continuous wave fields and rays with mixed polarization, or "entangled"
waves. The calculation assumes stationary lossless media with isotropic local
dispersion, but generalizations to other media are straightforward to do.
