  The E-mode (EE) CMB power spectra measured by Planck, ACTPol, and SPTpol
constrain the Hubble constant to be $70.0\pm2.7$, $72.4^{+3.9}_{-4.8}$, and
$73.1^{+3.3}_{-3.9}$ km s$^{-1}$ Mpc$^{-1}$ within the standard $\Lambda$CDM
model (posterior mean and central 68% interval bounds). These values are higher
than the constraints from the Planck temperature (TT) power spectrum, and
consistent with the Cepheid-supernova distance ladder measurement
$H_0=73.2\pm1.3$ km s$^{-1}$ Mpc$^{-1}$. If this preference for a higher value
was strengthened in a joint analysis it could provide an intriguing hint at the
resolution of the Hubble disagreement. We show, however, that combining the
Planck, ACTPol, and SPTpol EE likelihoods yields $H_0=68.7\pm1.3$ km s$^{-1}$
Mpc$^{-1}$, $2.4\sigma$ lower than the distance ladder measurement. This is due
to different degeneracy directions across the full parameter space,
particularly involving the baryon density, $\Omega_bh^2$, and scalar tilt,
$n_s$, arising from sensitivity to different multipole ranges. We show that the
E-mode $\Lambda$CDM constraints are consistent across the different experiments
within $1.4\sigma$, and with the Planck TT results at $0.8\sigma$. Combining
the Planck, ACTPol, and SPTpol EE data constrains the phenomenological lensing
amplitude, $A_L=0.89\pm0.10$, consistent with the expected value of unity.
