  We consider the practical feasibility of using the direct, electric
dipole-dipole interaction between co-trapped molecular ions for robust quantum
logic without the need for static polarizing fields. The use of oscillating
dipole moments, as opposed to static electric dipoles, dynamically decouples
the dipoles from laboratory fields, including the electric fields of the trap
itself. Further, this implementation does not require quantum control of
motion, potentially removing a major roadblock to ion trap quantum computing
scalability. Since the polarizing field is electromagnetic radiation, even
pairs of states with splittings in the THz regime can be fully polarized.
