A political activist in Washington, D.C. supporting Hillary Clinton – remembered locally as the man who stood outside the Washington Post building with a bullhorn yelling at the paper's editorial board – is challenging Democratic Sen. Bernie Sanders' access to the ballot.

Robert V. Brannum, a former schoolteacher who's served as the Chairman of the Ward 5 Democratic committee, uncovered a filing snafu that was the fault of the D.C. Democratic Party and filed a challenge one week ago.

The D.C. Democratic Party filed all the paperwork for its candidates, which included both Sanders and Clinton by 7 p.m. on March 16 per the rules of the Democratic National Committee, but the local D.C. Board of Elections closes at 4:45 p.m., explained D.C. Chairwoman Anita Bonds to the Washington Times.

Brannum said that means that Sanders was late and should be excluded from the Democratic primary ballot, according to his challenge.

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Sen. Bernie Sanders' place on the D.C. ballot is being challenged by a local activist who says the D.C. Democrats didn't file Sanders' paperwork on time

The local NBC News affiliate first reported the challenge with local party officials calling it a minor administrative dispute.

Both the Sanders and Clinton campaign had done their parts, paying the $2,500 by the specified deadline, which should have landed their candidates on D.C.'s June 14 ballot, the last primary contest in the country.

Robert V. Brannum doesn't think Bernie Sanders should be on the ballot for the District's Democratic June primary

Forty-five delegates are at stake

The Sanders campaign did not seem to be too concerned with a spokesman telling NBC News4 that 'We did what D.C. law requires in order to get Bernie on the ballot and we are confident he will be on the ballot.'

Bonds explained to the Washington Times that the D.C. City Council can pass 'clarifying legislation' to resolve the dispute, saying that the extended hours for submission are permitted.

Brannum was aware that this maneuvering was possible and railed against it in his challenge, writing that the 5 p.m. filing deadline is 'statutorily determinative and final.'

'To permit late filing is an injustice to the collective electorate of the District of Columbia and is unacceptable to District of Columbia voters,' he wrote.

'The time has come to break up the intellectually dishonest perception election laws of the District of Columbia can be bought,' he continued.

'To accept late filing perpetuates inequality and the protection of status quo shenanigans,' he added.

Robert Brannum has repeatedly defended Hillary Clinton on Twitter, blasting the media for negative portrayals of the female presidential candidate

Robert Vinson Brannum filed a challenge last week that said that Bernie Sanders missed the filing deadline and should be kept off the D.C. ballot

This isn't the first time that Brannum has rattled local party officials.

An uber-supporter for former D.C. Mayor Vincent Gray, Brannum even got himself arrested with the controversial mayor as they protested the District's lack of voting rights.

Brannum also protested the media's coverage of Gray, who lost to current D.C. Mayor Muriel Bowser in the city's last Democratic primary, targeting primarily the Washington Post.

'Upset by editorials from the Washington Post, Brannum repeatedly parked his car in front of the newspaper's building this summer to berate the editorial board via a bullhorn,' a Sept. 2011 Post article said, reporting on Brannum winning the chairmanship of the Ward 5 Democratic Committee.

'A choice that could make the District’s political establishment nervous,' the article explained.

More recently, Brannum has taken to Twitter to expose media bias in the coverage of Clinton.

He also wrote about the 'double standard' Clinton faces in a post for his examiner.com blog earlier this month.