"The vote was unanimous," said Sen. Bob Coffin, D-Las Vegas. "It was the product of a lot of discussion."

Horsford's challenge will be to bring Democrats into the majority in the 21-member Senate, a position they have not held since 1991.

There are five Senate Republican seats up for grabs in the general election, and Democrats are looking to target those held by Sens. Bob Beers, R-Las Vegas, and Joe Heck, R-Henderson. Both are completing their first terms.

Allison Copening, a second generation Las Vegan, is running against Beers. She serves as president of the board of directors for Child Focus, an organization that serves children living in the state foster care system.

No Democrat has yet filed against Heck.

Titus, a member of the state Senate since 1989, has served as minority leader since 1993.

The position became vacant with her announcement that she is a candidate for the 3rd Congressional District seat held by Rep. Jon Porter, R-Nev.

The 10 Senate Democrats would have to pick up one seat as well as hold on to their own five seats up for election to become the majority. Assemblyman David Parks, D-Las Vegas, has filed for Titus' Senate seat as has fellow Democrat Steve Nathan.

Republican Lou Toomin has filed for Titus' open seat as well.