Ohio voters rejected a ballot proposal Tuesday to legalize marijuana for both recreational and medical use.

The proposed state constitutional amendment failed after an expensive campaign, a legal fight over its ballot wording and an investigation into the proposal's petition signatures.

The measure known as "Issue 3" would have allowed adults 21 and older to use, purchase or grow certain amounts of marijuana. 

The constitutional amendment would have established a regulatory and taxation scheme while creating a network of 10 growing facilities -- a target of opponents, as well as a separate ballot question aimed at preventing monopolies from being inserted into Ohio's constitution for the economic benefits of a few.

The pro-legalization ResponsibleOhio campaign spent at least $12 million on ads. But it faced opposition from a well-organized, diverse coalition of opponents that includes children's hospitals, business organizations and farmers.

Critics said the proposal's arrangement would amount to an economic monopoly designed for personal gain.

The proposed amendment sparked huge political battles and made the Buckeye State ground zero for the cannabis controversy. 

"We spend all our time trying to tell kids to stay off drugs, and to legalize this drug sends such a mixed message," said Ohio Gov. John Kasich, a Republican presidential candidate and one of the initiative's biggest foes. "We can't afford mixed messages to our kids. So I'm totally opposed to this." 

Turnout was low as early presidential politicking largely overshadowed campaigns and exacerbated voter disinterest that generally accompanies an off-year election.

At an elementary school in the northern Cincinnati suburb of West Chester, Beth Zielenski, told the Associated Press she voted no on the marijuana question, citing concerns about how marijuana and edible pot products would be regulated.

Timothy Shearer, 47, said he voted for the initiative. "I don't think it will cause more problems," he said.

Colorado, Washington, Oregon and Alaska, along with the District of Columbia, have legalized recreational marijuana.

The Associated Press contributed to this report.