ALBANY — The GOP’s lone power base in state government is at stake in tomorrow’s races for the state Senate.

GOP bosses have poured more than $5 million and Democratic leaders about $1.5 million into key races around the state.

GOP leaders predict they’ll expand their 33-29 majority despite Democrats’ statewide enrollment advantage.

But Democrat Ted O’Brien holds a double-digit lead in a race to succeed a retiring Republican near Rochester, and Cecilia Tkaczyk is just 3 points behind GOP Assemblyman George Amedore for a new seat in the Albany area.