In other balloting, voters in California, Florida and Arizona approved constitutional amendments banning gay marriage.
In Arkansas, voters approved a ban on unmarried couples adopting or being foster parents.
Massachusetts voters approved decriminalizing possession of 1 ounce or less of marijuana. Under the new law, taking effect in 30 days, those caught must give up the marijuana and pay a $100 fine but won't face criminal penalties. Eleven other states have similar laws.
Michigan became the 13th state to allow residents — with a doctor's approval — to use marijuana to treat pain caused by cancer and other diseases.
Gambling, which gives states revenue without directly increasing taxes, was on the ballot in eight states. Maryland voters approved a measure that legalizes slot machines, dedicating half the revenue from up to 15,000 machines to public schools. Ohioans approved a state lottery to fund college scholarships.
Ohio voters, however, also rejected a measure approving a new casino. And in Massachusetts, citizens approved a ban on commercial dog racing.
Despite a weak economy, voters didn't necessarily embrace lower taxes. In Massachusetts, they rejected a measure to repeal the personal income tax, which supplies 40% of the state's budget. Democratic Gov. Deval Patrick warned it would force deep cuts in services statewide.
In South Dakota, voters rejected a ban on abortion, except in cases of rape, incest of when the woman's health was at risk.
California voters turned down a measure to require parental notification for a minor to get an abortion, while Colorado voters rejected a first-of-its-kind abortion measure that would define human life as starting "from the moment of fertilization."
In Michigan, a ballot asked voters whether they would amend the state's constitution to repeal its existing ban on research involving embryos.
Voters considered varying measures that affect immigrants, including one that Arizona rejected that would have revoked the business licenses of employers who knowingly hired illegal immigrants.
Missouri voted to make English the state's official language.
In Oregon, voters considered whether to limit the teaching of bilingual education to two years or less.
Contributing: Peter Eisler, in Raleigh, N.C.; Larry Copeland in Tampa; Marisol Bello in Detroit; Dennis Cauchon in Columbus, Ohio; Janet Kornblum in San Francisco; Mike Carney in Washington; Wendy Koch in McLean, Va.; the Associated Press