The President reportedly demanded Sessions’ resignation the moment he learned that Robert Mueller had been appointed special counsel in May, only to be dissuaded by his advisers. When recently asked if he planned to fire Deputy Attorney General Rod Rosenstein, the President replied, ‘You figure it out.’ The number three at the DOJ, Rachel Brand, resigned soon after.

Commentators suggest that Brand feared being next in line to fire Mueller. But confidantes of the President say that, while he used to moot firing Mueller, he now toys only with the idea of prosecuting the special counsel.

Professor of Law at New York Law School Rebecca Roiphe, a leading scholar of prosecutorial independence, offers this translation of the President’s comments. ‘“I'm using the DOJ as cover as long as they provide me with that cover… I'm letting them do what they are doing until or unless it undermines my presidency, in which case I'll interfere, which is my right.” It goes beyond undermining the independence of the DOJ to [saying that] the DOJ is there to serve a legitimating function for me… Which is a really autocratic thing to say when you think about it: “I have all these legal structures but they’re only there to give a semblance of legitimacy to my… power.”’

Roiphe is co-author of the academic paper, ‘Can the President Control the DOJ?’ She argues that the authority to allocate prosecutorial power lies with Congress. Having been silent on the question since it let the ‘independent counsel’ statute lapse in 1999, Congress may be understood as acquiescing on the issue of prosecutorial independence.

By Roiphe’s account, prosecutorial independence was built into the DOJ’s structure at two crucial points in its history. The reason the DOJ was founded, in 1870, was to shift prosecution from corrupt local offices to a professional central agency. A little more than a century later, after Nixon’s ‘Saturday night massacre’ compromised that agency, Congress expressly debated the balance between ensuring rule of law and democratic accountability. Congress rejected bills to outright remove the DOJ from the executive branch because it wanted to preserve accountability. Instead, America resolved to rely on prosecutorial norms to preserve the rule of law.

Congress concluded that what's going to save us from this happening again, says Roiphe, is ‘relying on the professional norms of prosecutors to make sure that this fundamental principle of prosecutorial independence serves as a kind of wall between the political intentions of certain elected officials and the administration of justice.’ But, the principle was only formalised in the DOJ’s internal regulations, which lack the force of hard law.

Norms are crucial in constraining the decision to prosecute, which is highly susceptible to partisan abuse and, because the decision process is secret, minimally subject to democratic accountability. ‘Whether to prosecute should not be a decision for political actors,’ says Roiphe. Roiphe is therefore troubled by a January report that the DOJ is gathering ‘new details’ on Hillary Clinton’s email use despite having repeatedly called it non-actionable. President Trump continues to encourage chants of ‘Lock her up!’ by conservative crowds. He taunted his own agency for not acting against her with the December tweet: ‘Many people in our Country are asking what the “Justice” Department is going to do about the fact that totally Crooked Hillary… deleted… 33,000 Emails? No justice!’

At this stage, renewed activity in the Clinton investigation may be dismissed as a still-independent agency throwing a bone to the President. But the danger of politicised prosecution rises as the President gradually disempowers people unwilling to play by his rules at every level of the federal government. Within the DOJ that process is most visible at the FBI. But it’s hardly confined to the FBI. In December, the DOJ demoted the director of organised crime drug enforcement for having met with ex-MI6 agent Christopher Steele about the ‘Russia dossier’. In January, the President appointed ten interim prosecutors without Senate approval to replace some of the US attorneys he had removed en masse. Among them were the three US attorneys best positioned to investigate the Trump and Kushner family businesses. Most notably, the President has replaced the fiercely independent Preet Bharara as US Attorney for the Southern District of New York with a partner at the same firm as Rudolph Giuliani, noted as a strong supporter of Trump during his 2016 campaign.

In their new book, How Democracies Die, Steven Levitsky and Daniel Ziblatt warn that ‘the erosion of democracy takes place piecemeal, often in baby steps.’ A big baby step indeed is ‘quietly firing… nonpartisan officials and replacing them with loyalists’.