The possession of small amounts of marijuana becomes legal starting Friday in Delaware, which joins 18 other states that have removed criminal penalties for carrying the drug. With four states and the District of Columbia having legalized recreational possession of cannabis in the last two years, reformers hope smaller steps like Delaware's will pave the way for the defeat of prohibition nationwide.

The Delaware state legislature in June passed a bill removing harsh criminal penalties for simple possession of up to an ounce of the drug, which had previously been punishable with three months in jail. It now becomes a civil violation with a fine, much like a traffic ticket.

“Delaware’s marijuana policy is about to become a lot more reasonable,” said Karen O’Keefe, who lobbied for the bill as state policies director for the Marijuana Policy Project, a Washington, D.C.-based group that works to reform cannabis laws. “Most people agree adults should not face jail time or the life-altering consequences of a criminal record just for possessing a substance that is safer than alcohol. Taxpayers certainly don’t want to foot the bill for it, and fortunately they will not have to any longer.”

However, there are still a number of circumstances under which Delaware police can arrest a person for having marijuana. Smoking cannabis in public is still a misdemeanor, punishable by less than a year in jail.

"People should do this in their own homes," state Sen. Margaret Rose Henry, a Democrat who helped sponsor the bill, told local news website Delaware Online earlier. "It should not be done in cars. It should be done in the privacy of your own home."

O’Keefe described the decriminalization lobby’s negotiations with lawmakers that left in the final draft some provisions police had wanted — especially the ability to continue to search a person caught with marijuana, even though possession will no longer be a criminal offense.

There is also a bit of fine print that allows for harsher prosecution of marijuana possession — but only for people between the ages of 18 and 21, for whom a second offense will draw an “unspecified misdemeanor” charge and a $100 fine. After they turn 21, they can petition to have their conviction expunged.

“We certainly didn’t agree with that,” O'Keefe said.

MPP will likely lobby for full legalization in the state instead of attempting to tweak the new law, she added.

Decriminalization has been a stepping stone to legalization and regulation of recreational pot use in other states, and Delaware law enforcement officials on Thursday expressed concerns that many state residents might overestimate the extent of the decriminalization law.

"There will be some confusion because people may think marijuana is legal now, and that is not the case," New Castle County Police Chief Elmer Setting told Delaware Online. "Hopefully, they read and understand the law."

Delaware is decriminalizing the drug in what could be a banner year for marijuana policy reform, with legalization laws and ballot initiatives on the horizon in several other states, including California, Maine and Massachusetts. In each state that has lifted criminal penalties for possession of small amounts of pot, decriminalization has served as a herald to an end to the prohibition.