By Fiona Ortiz

(Reuters) - Iowa's Supreme Court, in a 4-3 decision, on Thursday upheld the state's ban on voting for people with felony convictions, dismissing a claim from a woman who sued to be able to vote despite a conviction for a drug crime.

The majority opinion written by Chief Justice Mark Cady said in part, "we conclude our constitution permits persons convicted of a felony to be disqualified from voting in Iowa until pardoned or otherwise restored to the rights of citizenship."

The ruling bucks a trend around the country of restoration of voting rights that has drawn support from both Democrats and Republicans as a way to improve prisoners' reintegration into society.

Wyoming, California and other states have recently restored voting rights to felons convicted of nonviolent crimes. Iowa, Kentucky and Florida have the country's harshest rules, prohibiting all former felons from voting unless they secure an exemption from the governor.

The Iowa Supreme Court justices said they were interpreting the state constitution, which says people convicted of an "infamous crime" should be disqualified from voting.

"This conclusion is not to say the infamous-crime provision of our constitution would not accommodate a different meaning in the future. A different meaning, however, is not for us to determine in this case. A new definition will be up to the future evolution of our understanding of voter disqualification as a society, revealed through the voices of our democracy," the ruling said.

The ruling responds to a lawsuit filed by Kelli Jo Griffin, who was convicted in 2008 for distribution of cocaine, a class-C felony in Iowa. She was sentenced to probation, which she completed on 2013.

She registered to vote in 2013 and voted that November, but her ballot was rejected due to her felony conviction. She filed suit in 2014 against the governor and the secretary of state, asking the courts to declare that hers was not the type of conviction that disqualified a person from voting.

A district court rejected her claim, and the case went to the Supreme Court when Griffin asked for constitutional review.

The three dissenting justices wrote in their minority opinions that Griffin's crime did not fit the state constitution's definition of an infamous crime.

Laws governing felons' voting rights range considerably in the United States. Maine and Vermont allow prison inmates to vote, while Iowa and a handful of others have a lifetime ban on voting by convicted felons.

(Reporting by Fiona Ortiz; Editing by Jonathan Oatis)