Cosmic rays account for about 1/3 of the energy density in the interstellar medium of the Milky Way, and affect interstellar gas dynamics and thermodynamics significantly. Detection and modeling of nonthermal radio and gamma-ray emission from other galaxies and from galaxy clusters is making it possible to measure this fraction remotely and to test theories of cosmic ray acceleration and transport in other environments. I will discuss how cosmic rays are coupled to the ambient medium, assess where extensions of the coupling theory are needed, and show that the nature of cosmic ray coupling matters to the stability of interstellar gas and in driving galactic winds.