Silicon Valley Is Helping Expunge Marijuana Convictions

A conviction for growing marijuana turned Rob Jenkins' life upside down.

"The police ran in there and took my whole garden apart and trashed my whole apartment," Jenkins says of the 2008 raid on his Oakland, California, home. "I got a notice two weeks later that said get the hell out."

Jenkins was originally charged with a felony—he had a firearm in his home at the time of the raid—but the charges were dropped to a misdemeanor after law enforcement officials confirmed the gun was legally registered. He was...