  We present a joint analysis of Chandra X-ray observations, Bolocam thermal
Sunyaev-Zel'dovich (SZ) effect observations, Hubble Space Telescope (HST)
strong lensing data, and HST and Subaru Suprime-Cam weak lensing data. The
multiwavelength dataset is used to constrain parametric models for the
distribution of dark and baryonic matter in a sample of six massive galaxy
clusters selected from the Cluster Lensing And Supernova survey with Hubble
(CLASH). For five of the six clusters, the multiwavelength dataset is well
described by a relatively simple model that assumes spherical symmetry,
hydrostatic equilibrium, and entirely thermal pressure support. The joint
analysis yields considerably better constraints on the total mass and
concentration of the cluster compared to analysis of any one dataset
individually. The subsample of five galaxy clusters is used to place an upper
limit on the fraction of pressure support in the intracluster medium (ICM) due
to nonthermal processes, such as turbulence and bulk flow of the gas. We
constrain the nonthermal pressure fraction at r500c to be less than 0.11 at 95
percent confidence. This is in tension with state-of-the-art hydrodynamical
simulations, which predict a nonthermal pressure fraction of approximately 0.25
at r500c for clusters of similar mass and redshift. This tension may be
explained by the sample selection and/or our assumption of spherical symmetry.
