WASHINGTON - A debate over legalizing marijuana in the nation's capital is focusing on the outsized number of arrests of African Americans on minor drug charges.

Pot legalization supporters in Colorado and Washington state also spoke about racial justice, but their voters are mostly white and their campaigns focused more on other issues. The race factor hits closer to many more homes in the District, where nearly half the population is black.

And that means this referendum could change how the nation talks about marijuana, some drug-policy experts say.

"I think D.C. is going to probably set off a chain of events in which communities of color generally and cities in particular take on the issue of legalization as a racial justice, social justice issue in a much stronger way than they have so far," said Bill Piper, director of national affairs at the Drug Policy Alliance.

There are many other differences between the District and states which have legalized pot. The city is a patchwork of local and federal land, and there will be no lighting up in front of the White House or at the Jefferson Memorial. Also, Washington remains under the thumb of Congress, which could thwart the will of the voters as it has on other matters where liberal District tendencies clash with conservative priorities on Capitol Hill.

Nonetheless, the District is on track to join Colorado and Washington state in legalizing marijuana. A poll last month showed nearly two of every three voters favor the initiative, which will be on November's ballot. Voters in Alaska and Oregon also decide this fall whether to legalize pot.

Roughly half of the District's 646,000 residents are black. The American Civil Liberties Union found that in 2010, blacks were eight times more likely than whites to be arrested for marijuana possession in the District, and 91 percent of those arrested that year were black.

"It would alleviate a lot of problems," said Kenneth Agee, 46, a heating and air conditioning mechanic who plans to vote for legalization. "There may be less violence on the streets associated with marijuana trafficking and sales."

The D.C. Council tried earlier this year to address racial disparities by decriminalizing marijuana, as 17 states have done. Possession of up to one ounce of pot in the District is now subject to a $25 fine, among the lowest in the nation. The law took effect in July, despite an attempt by Rep. Andy Harris, a Maryland Republican, to block the measure.

Legalization advocates say decriminalization hasn't done enough, citing police statistics which show most of the $25 tickets are being distributed in predominantly black neighborhoods.

"We can tell the police, 'Guess what? It's not even a crime. You don't have to write a ticket,'" said Adam Eidinger, chairman of the D.C. Cannabis Campaign, the group that crafted the initiative and got it on the ballot.

The initiative also is notable for what it lacks. Because ballot initiatives in the District can't affect the budget, it does not provide for the legal sale of marijuana or set up a system to tax and regulate it. That would be up to the mayor and the council. Voters will also be choosing a new mayor in November to replace Vincent Gray, and both leading candidates have said they support legalization.

In Colorado and Washington state, the federal government said legal pot must be kept off federal property such as parks and other huge swaths of U.S. land. That could be more complicated in the District, where the situation can change from block to block. The parkland the federal government owns in the District, for instance, includes 59 inner-city squares and triangles.