District of Columbia residents embraced marijuana legalization Tuesday, overwhelmingly approving a ballot measure called Initiative 71.

The initiative allows residents age 21 and older to possess up to 2 ounces of marijuana and cultivate six plants at home – three of which may be mature and flowering – and has provisions for the noncommercial transfer of marijuana.

District ballot measures cannot appropriate city funds, so the initiative does not authorize a regulated recreational marijuana industry.

With 140 of 143 precincts reporting Tuesday evening, the legalization measure led with 64.7 percent of the vote, with just 28.4 percent voting against it.

The result is not a surprise. Polls consistently showed the measure with a sizable majority and the leading mayoral candidates, Democrat Muriel Bowser and independent David Catania, endorsed the measure.

The band of activists from the D.C. Cannabis Campaign who landed the initiative on the ballot did face challenges.

National marijuana reform groups offered little assistance and The Washington Post's editorial board in September asked voters to vote “no” and wait to see how legalization unfolds in Colorado and Washington. Residents of those states voted in November 2012 to legalize the drug, but recreational pot stores did not open there until this year.

Marijuana remains illegal under federal law, and federal law enforcement agencies – including the U.S. Park Police, which monitors large swathes of district land – will remain able to arrest people and slap them with federal charges, as they opted to do when the district lowered simple marijuana possession penalties to a $25 civil fine in July.

Legalization won’t take effect immediately in the district. The initiative must survive a congressional review period. To block the initiative, a resolution of disapproval would need to pass both the House and Senate during that time, a scenario that may be more likely if Republicans control of both chambers – though Sen. Rand Paul, R-Ky., says he opposes federal intervention to block the reform.

D.C. Council Chairman Phil Mendelson told the Washington City Paper he plans to submit the initiative to Congress in December or January.

A congressional attempt to block the voter-approved district initiative, even if successful, may prove futile.

In June Republicans on the House Appropriations Committee voted for a budget rider that would have blocked implementation of the district’s decriminalization law and the measure passed the House unchallenged. The rider died when the Senate did not consider the underlying bill, after its sponsor, Rep. Andy Harris, R-Md., admitted to U.S. News the district could choose any time it wishes to stop enforcing laws against marijuana – a plausible scenario if Congress votes to block the legalization initiative.

Congress is in a more powerful position when it comes to blocking district government-passed legislation allowing for recreational marijuana stores, and there will likely be a protracted struggle.

In what may become a close parallel, Congress blocked the opening of medical marijuana shops for years after district voters approved medical pot in 1998 (the city's first medical marijuana facilities opened in July 2013).

The district had a higher per capita marijuana arrest rate than any of the 50 states in 2010, according to an American Civil Liberties Union report released in June 2013. More than 90 percent of those arrested were black.

Marijuana was on the ballot across the country Tuesday. Guam voters approved medical marijuana, a first for a U.S. territory, while a majority of Florida voters also endorsed medical marijuana – though that measure failed to meet the 60 percent requirement for passage.

Editorial Cartoons on Marijuana View All 15 Images

Voters in South Portland, Maine, joined D.C. in voting to abandon local enforcement of small-time marijuana possession penalties, but Lewiston,Maine, rejected doing so. The Marijuana Policy Project touted the South Portland win – which follows a similar 2013 initiative in Portland – as de facto legalization.