Voters in the 40th legislative district vote Tuesday in a special primary for an open state Senate seat.
The 40th state Senate district seat is open after Juan Vargas won Mayor Bob Filner's vacant 51st District Congressional seat.
There are four qualified candidates: businessman Hector Raul Gastelum, professor/businesswoman/author Xanthi Gionis, California State Assemblymember Ben Hueso and nurse/author Anna Nevenic.
Democrats won two-thirds majorities in both houses of the Legislature last fall, but there is a chance at least one chamber may lack a supermajority for the rest of the year.
The uncertainty is caused by three open Senate seats -- and possibly a fourth -- and the musical chairs among Assembly members.
Senate Democrats currently are one seat short of the 27 they need to raise taxes, pass emergency legislation, override gubernatorial vetoes and put constitutional amendments before voters.
If Hueso wins a majority in the 40th Senate District and avoids a runoff they would regain that margin.