State Senate Republicans have muscled a surreptitious redraft of Virginia's 40 Senate districts to passage over bitter objections from Democrats who were blindsided by the surprise move.

On a party line 20-19 vote after limited debate Monday, Republicans won Senate passage of an amendment to a House bill that previously had made only minor technical corrections to district lines. The vote would have been a tie had Democratic Senator Henry Marsh been present. Marsh, a civil rights leader, was attending the inauguration in Washington.

After the measure was sprung on unsuspecting Democrats, its sponsor, Republican Sen. John Watkins of Powhatan, defended it as an effort to create another majority black Senate district. What he didn't say is that it would create even more GOP-dominant districts.

Democratic Sen. Don McEachin of Henrico called it "secretive and underhanded" and warned of a resumption of partisan discord that paralyzed the 2012 Senate. Each party holds 20 Senate seats.

The move could potentially eliminate at least one Democratic seat, according to Virginia politics blogger Ben Tribbett, who posted updates on his Facebook page: