  We formulate variation principle for force-free magnetosphere of an inclined
pulsar: ${\cal E} +{\bf \Omega}\cdot {\bf M}$ ($\cal E$, ${\bf M}$ are
electromagnetic energy and angular momentum, ${\bf \Omega}$ is the angular
velocity of a star) is stationary under isotopological variations of magnetic
field and arbitrary variations of electric field. The variation principle gives
the reason for existence and proves local stability of current singular layers
along magnetic separatrices. Magnetic field lines of inclined pulsar
magnetosphere lie on magnetic surfaces, and do have magnetic separatrices.
  In the framework of the isotopological variation principle, inclined
magnetospheres are expected to be simple deformations of the axisymmetric
pulsar magnetosphere. A singular line should exist on the light cylinder, where
inner separatrix terminates and outer separatrix emanates. The electromagnetic
field should have an inverse square root singularity near the singular line
inside the inner magnetic separatrix.
  Large distance asymptotic solution is calculated, and used to estimate the
pulsar power, $L\approx c^{-3}\mu ^2\Omega^4$ for spin-dipole inclinations
$\lesssim 30^{\circ}$ .
