As of Feb. 26, marijuana is legal in D.C.—sort of. Here are the ins and outs of the complex new pot law. (Gillian Brockell/The Washington Post)

As Thursday dawns on the nation’s capital, marijuana will be a legal intoxicant, though Washington will not be Amsterdam, or even Denver. There will be no pot shops, no open-air smoking, but at least for the moment, the District — for once in its decades-long struggle for the right to govern itself — has gotten its way, and a green rush is on.

Despite a last-hours intervention by the Republican chairman of the House committee that handles D.C. affairs, Mayor Muriel E. Bowser and D.C. Council members said Wednesday that they would not back down from implementing the will of the 70 percent of city voters who approved legalization in November.

Now, from private residences where Washingtonians may grow, possess and use small amounts of the drug to shops where budding entrepreneurs plan to sell accessories for cultivating marijuana plants, marijuana will quickly become a more overt part of the capital’s culture.

[FAQ: How to stay out of jail now that pot is legal in D.C.]

For advocates of legalization, the idea that weed can be legal in Washington is a breakthrough that will accelerate a similar embrace of the mind-altering plant in much of the nation. At least five states are moving toward legalization votes next year.

“What you’re seeing here is the end of marijuana prohibition, a change in attitudes and a real shift in law enforcement — a huge step forward in the national fight for legalization,” said Michael Collins, national policy manager for the Drug Policy Alliance.

“The nation’s capital has an exaggerated impact,” said Keith Stroup, legal counsel at NORML (the National Organization for the Reform of Marijuana Laws). “If Washington, D.C., can legalize marijuana and the sky doesn’t fall, things will get a lot easier in these other states.”

On the streets of the city, the big change actually took place in July, when the District decriminalized possession of small amounts of marijuana, meaning that someone caught with a joint or two faced a ticket rather than an arrest, handcuffs and a trip to court.

[Dvorak: A mom in a minivan goes in search of a pot party]

Relaxed enforcement

Since July 17, when the penalty for possession of less than one ounce went from up to a year in prison to a civil fine of $25, both D.C. police and their federal counterparts have essentially stopped going after people who have marijuana for personal use. Arrest data from the U.S. attorney’s office, which prosecutes drug offenses in the city, found that marijuana arrests in the District dropped from more than 15 a day to just over one a day after decriminalization.

In the first half of last year, law enforcement referred charges involving marijuana to prosecutors in 2,425 misdemeanor cases and 257 felony cases. From July 18 to the end of the year, arrests dried up, resulting in just 159 misdemeanor and 67 felony cases.

For the most part, D.C. police didn’t bother with the new marijuana citations, issuing fewer than 250 of them in the second half of the year. Even in public places, police may no longer use the smell of marijuana as probable cause for an arrest; an officer must directly observe someone smoking to make an arrest.

During a televised address, D.C. Mayor Muriel Bowser said that marijuana possession will become legal in the District at 12:01 a.m. Thursday, despite threats from House Republicans. (DCN)

Although the federal government owns roughly a quarter of the land in the District, and marijuana remains illegal on any federal property, federal arrests for pot possession have also fallen off a cliff since the city approved decriminalization.

U.S. Park Police reported 501 marijuana “incidents” in 2013, though many of those did not result in arrests. After decriminalization, Park Police were involved in 41 incidents last year, only three of which led to marijuana-related charges.

“Basically, police stopped arresting people, and the government stopped papering, unless it was with another charge, like carrying a pistol,” said Betty M. Ballester, head of the Superior Court Trial Lawyers Association, which represents defense lawyers.

Ballester and other defense lawyers have seen a marked change in how prosecutors handle pot cases as the government has repeatedly halted cases that were already in progress.

“They just came in on the day of trial and said they were not ready to proceed,” she said. “I think that was a policy decision.”

Decriminalization won support from then-Mayor Vincent C. Gray (D) and council members after a study by the American Civil Liberties Union showed a racially lopsided pattern of arrests for marijuana possession. Although surveys find that whites and blacks use the drug in roughly equal proportions, about nine out of 10 arrests in the District were of African Americans — a larger percentage than in any other major U.S. city.

Although arrests had already plummeted, legalization is nonetheless a pivotal moment for the nation and the city. Recreational marijuana is already legal in Colorado, Washington state and, since Tuesday, Alaska, but Congress’s decision to do nothing about the D.C. law during the 30-day review period that expired Wednesday marks a significant turning point, according to both sides of the legalization debate.

“A certain number of Republicans in Congress wanted to block D.C.’s marijuana initiative,” said Collins, who lobbies Congress on pot laws. “But the party’s leaders don’t want Republicans to become known as the anti-marijuana party.”

Collins and other lobbyists say Republicans on the Hill fall into three camps — a small group that strongly opposes liberalizing the law because of concerns about health and productivity; a larger group that wants to leave the issue to the states on libertarian and states’ rights grounds; and an ambivalent faction that doesn’t want to be viewed as falling behind public opinion on social issues.

“This opens the door across the country,” said DeForest Rathbone, chairman of the National Institute of Citizen Anti-Drug Policy, a Maryland-based group that favors existing drug laws. “Congress is afraid of acting because everybody thinks marijuana is harmless these days. People are going to regret this.”

‘Initiative 71 is . . . law’

A threat from congressmen with authority over the District seemed only to bolster the new D.C. mayor’s resolve. Rep. Jason Chaffetz (R-Utah), chairman of the House Oversight and Government Reform Committee, warned Bowser (D) to halt legalization or face “very severe consequences,” he told The Washington Post. “You can go to prison for this. We’re not playing a little game here.”

But Bowser made clear that she is keenly aware of her authority and intends to use it.

“I am the duly elected mayor of the District of Columbia,” she said upon taking the stage at a mid-afternoon news conference, during which she announced that the city would “implement and enforce” the law as passed by voters.

[Federal Eye: Pot’s legal in D.C. now. Does that change anything for federal workers?]

The city’s new attorney general, Karl A. Racine, and several council members stood with Bowser. “Initiative 71 is, in the attorney general’s view, law,” Racine said.

House Speaker John A. Boehner appeared to steer clear of the D.C. controversy; his spokesman, Michael Steel, said Boehner “deferred to the committee.” And Chaffetz’s Republican colleagues said they had no plans beyond the rhetorical warning.

“There’s no talk of litigation,” said Rep. Mark Meadows (R-N.C.), chairman of the subcommittee that handles D.C. affairs. But he warned that it could become “very difficult for D.C.” to get the money it needs on other matters. Congress can still act to roll back marijuana legalization through budget language.

Rep. Andy Harris (R-Md.), who earlier sought to block the city from spending money to implement the ballot initiative, said Attorney General Eric H. Holder Jr. “should prosecute people in the District who participate in this.” That seemed highly unlikely in an administration that has repeatedly signaled that it will let states conduct their own marijuana experiments.

Harris said the city’s planning for legalization may violate federal law against spending public dollars that haven’t been budgeted for that purpose. “Those people ought to be very afraid, because the penalties are severe,” he said.

[MAP | Where pot is still illegal: On federal land]

Bowser allowed that “me being in jail wouldn’t be a good thing, but making sure that the will of the voters is implemented . . . that’s my job and that’s what I’m doing.”

As the conflict between the city and its federal overseers develops, marijuana’s role in city life is already shifting. Although Congress has stopped the council from planning for eventual retail sales, entrepreneurs are charging ahead with plans to sell accessories used to grow and consume the plant.

Adam Eidinger, a leader in the legalization campaign, said he will reopen his Capitol Hemp store, which the city forced to shut down two years ago because he sold paraphernalia used to consume illegal drugs.

Eidinger said his new store, in Adams Morgan, will sell bongs, vaporizers and hemp products and will be more open about the purpose of its wares. In 2012, “if you said you were going to use the pipe for marijuana, we would tell you to leave,” he said. “We don’t have to play that game anymore.”

A marijuana industry exposition is scheduled to be held at a Capitol Hill hotel this weekend, part of what Stroup, the NORML counsel, called “the green rush.” Stroup said his group is getting calls from people who want to get into the business in Washington. He expects some entrepreneurs will test the limits of the law by establishing clubs where users pay a membership fee and are given the drug, in lieu of buying it directly. Bowser has called for legislation to block the formation of such clubs.

“Most marijuana smokers don’t want to smoke on their own at home,” Stroup said. “It’s a social act. So it will be up to the police and then the courts to decide what is public and what is private.”

Capital City Hydroponics, a small indoor gardening shop on Upshur Street NW in Petworth, already sells everything a gardener needs to grow vegetables and leafy greens. Now, said Michael Bayard, the owner, “we’re expecting volume to increase.”

Until now, when Bayard’s customers have come in asking how to grow marijuana, he has told them that he doesn’t provide that service. Bayard, valuing his relationships with local schools, still doesn’t want to be known as a pot store. Until he is sure legalization is here to stay, he won’t use marijuana leaf images in his marketing or openly talk about growing the plant.

“I don’t want to risk our livelihood,” he said. “The D.C. government works in funny ways. If you live here long enough, you know you don’t know what’s going to happen.”

Still, the store already sells fertilizers with packaging that looks as if it could be on a Grateful Dead poster and products called “Kushie Kush” and “Big Bud.” Bayard expects a rush of customers this weekend; he has ordered plenty of kits that could be used to cultivate marijuana at home. Prices range from $420 to $1,250.

Despite legalization, no one expects the black market to dissipate, especially since the D.C. law makes no provision for legal sale of the drug. One District dealer, a 24-year-old whose day job is with a government contractor, said he expects to continue selling about four ounces a week.

He believes that legalization will make it much less likely that he will be caught selling illegally. He said it will now be easier to hold and transport the drug because he’ll limit his own possession to the legal maximum of two ounces. And he expects customers will buy in larger quantities than the standard one-eighth ounce, which he sells for $60.

“This makes it easier to stay in because it’s safer,” the dealer said.

Mike DeBonis and Peter Hermann contributed to this report.