BILLINGS — Montana’s high court struck down a voter-approved victims’ rights law as unconstitutional on Wednesday, in a split opinion that said voters should have been able to consider the multiple aspects of the law individually.

The law, dubbed Marsy’s Law, sought to give crime victims and their families the right to participate in judicial proceedings and to be notified of key developments in a case. It also would have expanded their privacy rights.

But justices said in a 5-2 opinion that the law would have made multiple changes to the Montana Constitution that should have been considered separately.

More than 65 percent of voters backed the law in an initiative last November. It had been put on hold by the court in June following a lawsuit from the Montana Association of Counties, the American Civil Liberties Union and others.

In striking it down, the court said its decision was based on how the law was presented to voters — not the merits of the changes themselves.

The state constitution “clearly grants the people the initiative power to popularly amend the Constitution,” Justice Laurie McKinnon wrote on behalf of the majority. “However, the procedure by which the Montana Constitution is amended must comply with existing constitutional requirements.”

The Attorney General’s Office had defended the law on behalf of voters.

Dissenting Justices Jim Rice and Beth Baker said the law was not ready for review because it hadn’t been implemented and its effects would not be known until it was applied to particular cases.

The law is named after Marsy Nicholas, a California college student who was killed by her ex-boyfriend in 1983.

Her brother, Broadcom Corp. co-founder Henry Nicholas, campaigned to pass Marsy’s Law first in California in 2008 and is pushing to enact it in more.