  A complete numerical description of the charge and spin dynamics of a
two-electron system confined in narrow nanowire quantum dots under oscillating
electric field is presented in the context of recent electric dipole spin
resonance experiments. We find that the spin-orbit coupling results in lifting
the spin blockade by phonon mediated relaxation provided that the initially
occupied state is close in energy to the ground state. This leads to
suppression of the blockade from the triplet state with spins polarized
parallel to the external magnetic field B. At higher B, after singlet-triplet
ground-state transition a new channel for lifting the Pauli blockade opens
which results in an appearance of additional resonance lines. The calculated
signatures of this transition are consistent with recent experimental results
[S. M. Frolov et al., Phys. Rev. Lett. 109, 236805 (2012)].
