The District of Columbia is poised to join the growing rank of states that have legalized marijuana.

The D.C. Elections Board voted unanimously Wednesday to add an initiative on the Nov. 4 ballot that would allow people 21 and older to possess and use of up to two ounces of cannabis and to grow up to six marijuana plants at home.

Mayor Vincent Gray already this year signed a decriminalization law that makes possession of less than one ounce of marijuana a civil offense punishable by a $25 fine.

But several members of Congress have been trying to block the District’s push to legalize pot. Rep. Andy Harris, R-Md., added an amendment to an appropriations bill this year that would bar D.C. from spending money to liberalize pot laws.

The congressman, a physician, said his measure is intended to protect teenagers from easy access to drugs.

“When I became a physician, I took an oath to do no harm, and decriminalizing marijuana will harm D.C. residents, especially teens,” said Harris last month after his measure and the overall bill passed the House.

“We should be doing all we can to protect the health and safety of teens throughout the District — and the language in this bill will help us do that.”

The spending measure is likely to die in the Democratic-controlled Senate.

D.C. congressional Del. Eleanor Holmes Norton, a Democrat, has vowed to fight any congressional attempt to block the District from voting on the initiative and, if it's approved by voters, from implementing it.

“We will not let history repeat itself,” Norton said Wednesday. “Republicans tried to prevent D.C. from voting on an initiative in 1998 to legalize medical marijuana, and after voters approved it, blocked its implementation with an appropriations rider for more than 10 years.”

Norton said GOP opposition to the ballot initiative smacks of hypocrisy because of the party’s longstanding tradition of supporting state and local rights over federal intrusion.

“Many Republicans abandon their professed support of local control of local affairs when they have an opportunity to bully the residents of the District, who cannot hold them accountable at the ballot box,” said Norton, referencing D.C.'s lack of a voting member in Congress.

The fight comes amid growing support for reducing restrictions on marijuana.

Twenty-three states have legalized medical marijuana, 18 states have decriminalized pot, and two states — Colorado and Washington — have legalized the drug.

A February Pew Research Center poll found that 54 percent of Americans support marijuana legalization.