Deputy Attorney General Rod J. Rosenstein. (Melina Mara/The Washington Post)

Harry Litman teaches constitutional law at the University of California at San Diego. He served as deputy assistant attorney general in the Justice Department from 1993 to 1998 and U.S. attorney for the Western District of Pennsylvania from 1998 to 2001.

In recent weeks, Deputy Attorney General Rod J. Rosenstein has capitulated to political pressure from the president and his allies in Congress. He has yielded to demands from the most rabid opponents of special counsel Robert S. Mueller III’s probe in a way that harms the long-term interests of the Justice Department and likely does little to protect the probe or Rosenstein’s own job.

To be fair to Rosenstein, he is under enormous, improper pressure from his ultimate boss, the president of the United States, as well as a venomous group of congressional Republicans, led by Rep. Devin Nunes (R-Calif.). And he had previously safeguarded Mueller’s ability to complete his mission, resisting political pressure from the White House.

But now he has made two critical missteps. First, he permitted Nunes and Trey Gowdy (R-S.C.), leaders on the House Intelligence Committee, to review the two-page memo that activated the FBI’s ongoing counterintelligence investigation of contacts between Russia and the Trump campaign. It is extremely rare for the department to share a memo on the opening of a investigation when that investigation is still active. The Justice Department had resisted Nunes’s demand, which President Trump had endorsed on Twitter.

Second, and even more worrisome, Rosenstein on Thursday agreed to release to Nunes and company former FBI director James B. Comey’s memos of his conversations with Trump. Like the two-page memo, Comey’s notes are also documents pertaining to an active investigation. As expected, within minutes the Comey memos were then leaked to the public.

While requests from Congress are always subject to some ad hoc back-and-forth, it is about as hard and fast a rule as there is that the Justice Department will not hand over documents relating to a still-active investigation. And for good reason: It could compromise the investigation, unfairly expose uncharged individuals and provide a road map for defendants to sculpt their stories. It is precisely that the practice is inflexible and long-established that provides department officials the wherewithal to resist the often urgent saber-rattling calls from the Hill to provide documents in pending investigations. Rosenstein departed from the policy for frankly political reasons. The House Intelligence Committee threatened to hold him in contempt, with the acrid prospect that the move would lay the groundwork for Trump to dismiss him and install a Trump ally atop the Mueller probe.

This capitulation alters the balance of power between the Justice Department and the Hill and makes it substantially more difficult for department officials to resist future congressional interference in active, politically charged investigations. It may also be that Rosenstein acted to protect the probe based on considerations that we don’t know about. Even so, it’s a miserable day at the Justice Department when the deputy attorney general is forced at gunpoint to turn over important evidence in a pending criminal investigation.

What made the decision especially perverse is that Rosenstein knew that his antagonists aimed to use the material to discredit the Mueller probe in particular and further their zealous attack on the Justice Department and federal law enforcement generally. Sure enough, the Comey memos leaked almost instantly, and Trump and his supporters have incorrectly trumpeted that they exonerated Trump of obstruction of justice.

Rosenstein’s tenure is a testimonial to the perils of trying to play ball with the president and his congressional allies. He began his time in office being manipulated into supplying at the president’s demand a memo arguing for Comey’s firing that the president used, falsely, to justify the action. He wound up looking like a stooge. Having been burned, Rosenstein thereafter put his head down and set his sail by Justice Department practices and culture. Starting with the splendid selection of Mueller, he quickly became a stand-up Justice Department loyalist.

The more recent decisions appear to be a reversion toward succumbing to political pressure from the White House and Congress. The problem isn’t simply that these errors depart from principle. It is also that they are very risky on their own terms. The record of those who seek to curry favor with the president is dismal. Trump seems to take special relish in belittling former antagonists who have stooped to kiss his hem — just ask Chris Christie, Mitt Romney or Jeff Sessions. Trump has already laid the groundwork for Rosenstein’s discharge, alleging that he is the “most conflicted of all” the players in the Mueller probe. And indeed, news reports from last week quote a source close to Trump as saying the president hasn’t “cooled off” on Rosenstein and that Rosenstein may be “about to be spit-roasted.” He would not be the first victim, but he would be the most consequential, of the president’s endless spite and viciousness.