  In framework of a variational method the molecular ion $H_2^+$ in a magnetic
field is studied. An optimal form of the vector potential corresponding to a
given magnetic field (gauge fixing) is chosen variationally. It is shown that
for any magnetic field strength as well as for any orientation of the molecular
axis the system $(ppe)$ possesses a minimum in the potential energy. The stable
configuration always corresponds to elongation along the magnetic line.
However, for magnetic fields $B \gtrsim 5\times 10^{11} G$ and some
orientations the ion $H_2^+$ becomes unstable decaying to $H{-atom} + p$.
