  A proof of strong cosmic censorship is presented for a class of solutions of
the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key
element of the argument is the observation that by means of a suitable choice
of variables the central equations in this problem can be written in a form
where they are identical to the central equations for general (i.e.
non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the deep
results of Ringstr\"om on strong cosmic censorship in the vacuum case have
implications for the Einstein-Maxwell case. Working out the geometrical meaning
of these analytical results leads to the main conclusion.
