Ms Manning has said the US needs an "unapologetic progressive leader"
US President Donald Trump has criticised whistleblower Chelsea Manning, who he described as an "ungrateful traitor".
In his final days of office, Barack Obama commuted the 35-year sentence of the former US Army intelligence analyst, who leaked thousands of documents to WikiLeaks.
She had not been due for release until 2045, and will have served seven years when she is released in May.
Today, President Trump took to Twitter to criticise the whistleblower.
Ungrateful TRAITOR Chelsea Manning, who should never have been released from prison, is now calling President Obama a weak leader. Terrible!— Donald J. Trump (@realDonaldTrump) January 26, 2017
Although the tweet did not offer any context, his comments come a day after Ms Manning published her first column since Obama's decision.
In The Guardian, she writes: "Barack Obama left behind hints of a progressive legacy. Unfortunately, despite his faith in our system and his positive track record on many issues over the last eight years, there have been very few permanent accomplishments.
"The one simple lesson to draw from President Obama’s legacy: do not start off with a compromise. They won’t meet you in the middle. Instead, what we need is an unapologetic progressive leader," she argues.
She has previously thanked Obama for his decision, which followed intense campaigning from transparency activists.
Thank you @BarackObama for giving me a chance. =,)— Chelsea Manning (@xychelsea) January 19, 2017
Explaining his decision to commute the sentence, Obama told reporters: "Let’s be clear, Chelsea Manning has served a tough prison sentence. So the notion that the average person who was thinking about disclosing vital, classified information would think that it goes unpunished I don't think would get that impression from the sentence that Chelsea Manning has served.
"With respect to Chelsea Manning, I looked at the particulars of this case the same way I have for the other commutations and pardons that I've done, and I felt that in light of all the circumstances that commuting her sentence was entirely appropriate," he added.