Sen. Ann Cummings, of Washington County, is challenging Senate President Pro Tempore John Campbell, of Windsor County, for the job Campbell has held for the last two years.
A Tuesday vote is planned by the Democrats. The full Senate will vote on the leadership position in January.
Cummings says she's seeking the job held by Campbell because of what she calls the "dysfunction" of the last two years.
Campbell, meanwhile, said he believes he has the votes to win re-election, but he says he's heard the complaints about how the chamber has been run and he's promising to make changes.