WASHINGTON — It is fitting that the day before President Barack Obama gives his grand West Point address defending the wisdom and prudence of his foreign policy, his government should be urging Americans to evacuate Libya. Libya, of course, was once the model Obama intervention — the exquisitely calibrated military engagement wrapped in the rhetorical extravagance of a nationally televised address proclaiming his newest foreign policy doctrine (they change to fit the latest ad hoc decision): the responsibility to protect. You don’t hear R2P bandied about much anymore.