A write driver for writing to a spin-torque magnetoresistive random access memory (ST-MRAM) minimizes sub-threshold leakage of the unselected (off) word line select transistors in the selected column. An effective metal resistance in the bit line and/or source line is reduced and power supply noise immunity is increased. Write driver bias signals are isolated from global bias signals, and a first voltage is applied at one end of a bit line using one of a first NMOS-follower circuit or a first PMOS-follower circuit. A second voltage is applied at opposite ends of a source line using, respectively, second and third PMOS-follower circuits, or second and third NMOS-follower circuits.