  We attempt to make a direct measurement of the weak lensing signal from the
WMAP 7-year data. We apply the real-space implementation of the optimal
quadratic estimator on the maps produced by the W-band Differencing Assemblies.
We obtain a weak lensing amplitude parameter of $A_{L}=0.99\pm1.67$ after
correcting for several sources of bias. The error budget includes a
contribution from the bias removal procedure. Despite the demonstrated
insensitivity of the real-space estimator to uncorrelated noise, we conclude
that this detection is not statistically significant. We expect that a
full-sky, higher-sensitivity experiment such as Planck will allow us to make a
more significant measurement.
