  The two-photon interferometric experiment proposed by Franson [Phys. Rev.
Lett. 62, 2205 (1989)] is often treated as a "Bell test of local realism".
However, it has been suggested that this is incorrect due to the 50%
postselection performed even in the ideal gedanken version of the experiment.
Here we present a simple local hidden variable model of the experiment that
successfully explains the results obtained in usual realizations of the
experiment, even with perfect detectors. Furthermore, we also show that there
is no such model if the switching of the local phase settings is done at a rate
determined by the internal geometry of the interferometers.
