While Washington gears up to open licensed recreational marijuana shops in July, it’s an interesting time to look back on the state’s recent history leading up to pot’s legalization.

Look no further than Riley Morton’s hard-charging but enlightening documentary “Evergreen: The Road to Legalization.” A taut, thorough chronicle of the 2012 campaign to pass Initiative 502 — which proposed legalizing possession of small amounts of marijuana for recreational use — “Evergreen” is an energetic study of a hard-fought battle.

Many opponents of I-502, the film shows, turned out not to be anti-marijuana forces but rather people who believed the ballot measure didn’t go far enough to loosen penalties, even containing some traps that could cause moderate users to be arrested.

Morton is fair to all parties, and the first thing that strikes a viewer is the array of local leaders and influential voices who participated in the fight. Among the proponents of I-502 were Alison Holcomb, an American Civil Liberties Union lawyer and I-502’s director, and beloved travel guru Rick Steves, a longtime critic of failed war-on-drugs policies. Together, they travel the state making the case for I-502 at town-hall meetings.

Save 75% on a Digital Subscription Today

The brusque opposition is largely represented by medical-marijuana provider Steve Sarich and defense lawyer Douglas Hiatt. Both make a strong case that provisions in I-502 regarding Driving Under the Influence (DUI) thresholds are unrealistic.

Of course, possible discrepancies between Washington’s take on marijuana and that of the federal government hang over this drama as well.

In the end, “Evergreen” is a lively story about passion and political compromise: I-502 supporters maintain the initiative, which passed despite its problems, was the best and only way to break the stranglehold of drug laws filling prisons for simple possession. Hiatt, on the other hand, calls passage a Pyrrhic victory. We’ll see.

Tom Keogh: tomwkeogh@yahoo.com