  Effects of charge-density fluctuations on a phase behavior of the restricted
primitive model (RPM) are studied within a field-theoretic formalism. We focus
on a $\lambda$-line of continuous transitions between charge-ordered and
charge-disordered phases that is observed in several mean-field (MF) theories,
but is absent in simulation results. In our study the RPM is reduced to a
$\phi^6$ theory, and a fluctuation contribution to a grand thermodynamic
potential is obtained by generalizing the Brazovskii approach. We find that in
a presence of fluctuations the $\lambda$-line disappears. Instead, a
fluctuation-induced first-order transition to a charge-ordered phase appears in
the same region of a phase diagram, where the liquid -- ionic-crystal
transition is obtained in simulations. Our results indicate that the
charge-ordered phase should be identified with an ionic crystal.
