  There are many situations in which mis-coordinated strategic voting can leave
strategic voters worse off than they would have been had they not tried to
strategize. We analyse the simplest of such scenarios, in which the set of
strategic voters all have the same sincere preferences and all cast the same
strategic vote, while all other voters vote sincerely. Most mis-coordinations
in this framework can be classified as instances of either strategic
overshooting (too many voted strategically) or strategic undershooting (too
few). If mis-coordination can result in strategic voters ending up worse off
than they would have been had they all just voted sincerely, we call the
relevant strategic vote unsafe. We show that under every onto and
non-dictatorial social choice rule there exist circumstances where a voter has
an incentive to cast a safe strategic vote. We extend the Gibbard-Satterthwaite
Theorem by proving that every onto and non-dictatorial social choice rule can
be individually manipulated by a voter casting a safe strategic vote.
