Attorney General William Barr’s decision on Tuesday to name John Durham, the U.S. attorney for the District of Connecticut appointed by President Trump, as special counsel to investigate matters surrounding the 2016 election violates the rules for special counsels as well as fundamental democratic principles.

There may be reasons the inquiry by Mr. Durham — an investigation that began in 2019 into the Trump-Russia inquiry — should continue, but there is absolutely no reason to permit an outgoing attorney general to try to install his preferred personnel at the investigation’s helm in the new administration. And it is entirely appropriate for President-elect Joe Biden to appoint all the prosecutors in his new administration, just as his predecessors have done.

The special counsel regulations, which I drafted in 1999 as a Justice Department staff member, were designed with the idea that some investigations require a person from outside the department to assure the public of sufficient independence. We had in mind circumstances in which, for example, a president was alleged to have engaged in wrongdoing and having his attorney general conduct the investigation could cause a problem with impartiality. That is why they expressly require someone “outside the United States government” to serve as special counsel. Doing so helps reassure the public of an independent investigation.

There are other models; sometimes a person from inside the department investigates, as the Justice Department did in 2003 with the Valerie Plame scandal. But none of these models, special counsel or otherwise, was designed to let an attorney general “burrow” his handpicked prosecutor into a new administration. And no internal Justice Department regulation can prevent a new president from dismissing a prosecutor, including Mr. Durham.

The reason for using any of these models, especially the special counsel one, is really the opposite of Mr. Barr’s apparent goal. They are designed to insulate from politics serious investigative work that needs to be done. But Mr. Barr has asked Mr. Durham to cover ground that has already been explored in detail by the department’s inspector general. As if that wasn’t enough, Mr. Barr and Mr. Durham denigrated an element of the inspector general’s findings even as Mr. Durham’s own investigation continued, in a remarkable break with a longstanding department norm of not commenting on a continuing criminal investigation and not simply rejecting the findings of an inspector general.

So far as anyone can tell, after months of work, Mr. Durham’s effort appears not to be investigative work that requires insulation from politics but political work that Mr. Barr now wants to insulate from investigative scrutiny. That stands the special counsel model on its head and underscores why he should not receive the “special counsel” designation.

There are two other glaring problems with the Durham appointment. One is that the predicate for the appointment of a special counsel is a “conflict of interest for the department or other extraordinary circumstances” and that it be “in the public interest to appoint an outside special counsel.” Mr. Barr did not hardly bother trying to meet these rules; he just did it anyway.

A second problem is that a special counsel must be “a lawyer with a reputation for integrity and impartial decision making.” Mr. Durham entered this inquiry with that reputation, earned for work under both Republican and Democratic administrations. But Mr. Durham’s top aide in the investigation, the well respected Nora Dannehy (who certainly fits that bill), “quietly resigned — at least partly out of concern that the investigative team is being pressed for political reasons to produce a report before its work is done,” according to colleagues. Whatever the circumstances of Ms. Dannehy’s departure, the special counsel regulations are all about public perception, and here they all stink.

In this case, all three of the problems with the special counsel rules are mutually reinforcing. Mr. Durham, as a political appointee from inside the U.S. government, has a serious appearance issue in conducting this investigation. The predicate for a special counsel does not appear to be triggered — instead it looks like the willful act of an outgoing attorney general. And when the Dannehy resignation is layered on top of that, it makes this special counsel appointment more dubious than any I can recall.

The Durham action here is of a piece with other attempts by the Trump administration to burrow in both personnel and policy in its last days, including the attempted installation of a new general counsel at the National Security Agency who played a role in the run-up to Mr. Trump’s impeachment. That move has prompted congressional calls for investigation. The administration is also grotesquely rushing to execute a number of federal inmates. It is trying to burrow many political appointees into Civil Service positions so that they can remain in the government. And it is adopting regulations and foreign policy activities that are hard to undo.

All of this is in tension with democratic principles, and the idea that the people elect a president to set these policies and select personnel. It’s a devious move designed to entrench a politically appointed prosecutor in a new administration and to make it hard for President Biden to appoint a replacement. And it’s in tension with how the Trump team itself was treated as it took office, with some foreign policy decisions — like whether to increase American support to anti-Islamic State forces in Syria — being left for Mr. Trump after his national security advisers were specifically asked whether they’d prefer that and indicated that they would.

Mr. Durham, for his part, exists as a legal patchwork — an amalgamation of some special counsel rules and some rules of Mr. Barr’s own doing. In the end, this jury-rigged prosecutor is one with little legal precedent or authority, and he can easily be dismissed in the new administration and, if needed, replaced by someone who adheres to all the special counsel regulations in his stead.

Neal K. Katyal (@neal_katyal), a former acting solicitor general of the United States and the author of “Impeach: The Case Against Donald Trump,” is a law professor at Georgetown.

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