The state Conservative Party has helped drive challenges to three upstate Republican senators who sided with Democratic Gov. Andrew M. Cuomo in the gay marriage vote: Mark Grisanti of Erie County, Stephen Saland of Poughkeepsie, and Roy McDonald of Saratoga County.
And there is an unusual number of contests without incumbents because more than 20 of 150 Assembly members and four of 62 senators have retired or resigned this term.
Turnout Thursday was expected to be low, making many of the races unpredictable. The primary usually held on Tuesdays was moved to Thursday in observance of the Sept. 11 anniversary of the terrorist attacks.
The GOP Senate races feature arguments the incumbents betrayed their party's principles by voting for gay marriage.
Republicans hold a 33-29 majority in the Senate.
In the Democrat-led Assembly, a few Republicans are testing the public's reaction to a sexual harassment scandal involving Democratic Assemb. Vito Lopez and Assembly Speaker Sheldon Silver's role in paying $103,000 in public funds to settle sexual harassment allegations against Lopez, who has denied any wrongdoing.