Risen's tweets were referring to Holder's comments concerning national security and freedom of the press in conjunction with the Obama administration overseeing a number of prosecutions of government whistle blowers.
Risen's history with Holder and the Department of Justice traces back to his battle with the DOJ not to reveal a source in a book about the CIA's effort to sabotage Iran's nuclear weapons, a work that put Risen in danger of jail time for years.
In an editorial for The New York Times, the paper's public editor Margaret Sullivan wrote that while their reporters generally aren't supposed to editorialize on issues they cover, she commended his intent, noting his passion for truth:
Because of his personal experiences, someone like James Risen has an obligation to speak out strongly on press rights. And I think more journalists ought to join him in that passion.
Maybe the tenor of Mr. Risen’s tweets wasn’t very Timesian. But the insistence on truth-telling and challenging the powerful is exactly what The Times ought to stand for. Always.
Watch Holder's comments that sparked Riesn's tweets here: