Chelsea Manning, the transgender U.S. Army soldier who served seven years in military prison for leaking classified data, is seeking the Democratic Party's nomination for the U.S. Senate seat in Maryland, according to Federal election filings seen on Saturday.

Manning, who was granted clemency by former U.S. President Barack Obama, was released in May from a U.S. military prison in Kansas where she had been serving time for passing secrets to the WikiLeaks website in the biggest breach of classified data in the history of the United States.

Democratic Senator Ben Cardin was elected in 2006 to that seat and is expected to run for re-election this year. He is the senior Democrat on the Senate Foreign Relations Committee.

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Chelsea Manning is seeking the Democratic Party's nomination for the U.S. Senate seat from Maryland. She is pictured speaking during the Nantucket Project's annual gathering in September

Manning came out as transgendered shortly after her sentencing, but the military denied her request for hormone therapy treatment while behind bars. Pictured before she transitioned

Cardin was easily re-elected in 2012, beating his Republican challenger by 30 points in the heavily-Democratic state.

Manning had been working as an intelligence analyst in Iraq.

She was convicted by court-martial in 2013 of espionage and other offenses for furnishing more than 700,000 documents, videos and diplomatic cables to WikiLeaks, an international organization that publishes information from anonymous sources.

She came out as transgendered shortly after her sentencing, but the military denied her request for hormone therapy treatment while behind bars.

She was placed in solitary confinement after attempting suicide twice.

Newsmaker of the Year Chelsea Manning speaks on stage during OUT Magazine #OUT100 Event presented by Lexus at the the Altman Building on November 9, 2017 in New York City

In a 'Nightline' interview with Juju Chang after her release, Manning was asked what she would say to Obama if she had the chance to speak with him after he commuted her prison sentence prior to leaving office.

She immediately began sobbing at the mention of Obama's name, before saying: 'Thank you for giving me a chance. That's all I wanted.'

Manning, 30, continued to cry as she then added: 'That's all I asked for was chance, that's it. And this is my chance.'

Her initial prison sentence had been for 35 years, the longest term ever handed down to a leaker in the United States, but thanks to Obama she was released after just seven years behind bars.

When the former army intelligence officer was asked if she believed that she owed Americans an apology for her actions, she replied: 'I've accepted responsibility. No one told me to do this. Nobody directed me to do this.'

She then added: 'This is me. It's on me.'

Democratic Senator Ben Cardin (pictured) was elected in 2006 to that seat and is expected to run for re-election this year. He is the senior Democrat on the Senate Foreign Relations Committee

Manning was asked if she was ever concerned that the over 700,000 documents she leaked to Wikileaks would threaten national security.

'No,' said Manning, who opted not to expound upon her answer.

Chang then asked Manning to respond to her detractors, who believed that by leaking these documents Manning was potentially giving top-secret information to enemies of the United States.

'Right, but I have a responsibility to the public,' explained Manning.

'You know, it's not just about me. We all have responsibility.'

Manning explained that at the time, she had hoped the release of the documents would cause public debate, and raise awareness.

'I work with this information every day. I'm the subject matter expert for this stuff,' said Manning.

'You know, we're the ones who work with it the most. We're the most familiar with it. It's not, you know, it's not a general who writes this stuff.'