A disputatious reporter seeks access to the White House but is blocked by Secret Service. Debate ensues over the journalist’s tactics and whether he presents a physical threat more menacing than the pummeling that issues from his pen, or his microphone. The government doesn’t offer a clear account and is sued on First Amendment grounds.

CNN’s Jim Acosta isn’t the original protagonist in this drama, which is roiling Washington and drawing stern warnings from the likes of Bob Woodward. While the controversy, like so many others with President Trump at their center, appears to occupy uncharted territory, it actually doesn’t.

A case cited in the network’s complaint against Trump, as well as members of his administration and the Secret Service, points to an important precursor, which holds clues about the viability of CNN’s suit, filed Tuesday.

The case is Sherrill v. Knight, decided in 1977 by the U.S. Court of Appeals for the District of Columbia Circuit. It’s still good law in the district where CNN filed its suit, to which the White House is supposed to respond by 11 a.m. Wednesday, according to an order from Timothy Kelly, a former attorney for the Senate Judiciary Committee who was named by Trump to the federal bench last year.

In the 1977 case, the court found that denial of White House credentials was a sufficiently grave infringement on the freedom of the press that it couldn’t just be done by fiat. It required, at the very least, “notice of the factual bases for denial, an opportunity for the applicant to respond” and “a final written statement of the reasons for denial.” Notably, the court prohibited “content-based criteria for press pass issuance.”

The critical finding, according to Mark H. Lynch of Covington & Burling, who argued the case before the D.C. Circuit, was this: Given the “important First Amendment rights implicated by refusal to grant White House press passes to bona fide Washington journalists,” as the court held, “such refusal must be based on a compelling governmental interest.”

“Under the circumstances of the Acosta denial, the government is not going to be able to meet that standard,” Lynch predicted in an email exchange with The Washington Post.

Lynch, then an attorney with the American Civil Liberties Union, represented the late Robert Sherrill, an ink-stained contrarian who bore little resemblance to the CNN White House correspondent — except on the important point that he was an irritant to the White House.

Acosta has worn that identity proudly. “If I may ask one other question,” he said at Trump’s post-midterms news conference last week, as the president sought to move on, telling him, “That’s enough.”

The exchange prompted the administration to yank the reporter’s credentials, falsely accusing him of “placing his hands” on a White House intern who had tried to seize his microphone.

Acosta, who has been accused of showboating, didn’t yield. On-screen and on social media, his tactics are tailor-made for the modern media environment.

And his employer has his back. “Plaintiffs bring this action to enforce this constitutional commitment, restore Acosta’s well-deserved press credentials, and ensure that the press remains free to question the government and to report the business of the nation to the American people,” the network explained in its complaint.

Sherrill’s persona was different, yet there are parallels. Once called an “inexhaustible loner of Washington journalism,” he cut the capital’s larger-than-life figures down to size in books that earned him the ire of his subjects, including Lyndon B. Johnson and Hubert H. Humphrey. A muckraker, he exposed American greed and folly in investigations into military judicial abuses and the oil and gun industries.

A self-described “independent radical journalist,” he used caustic wit to document unseen suffering. “Since the Depression,” he wrote in the New York Times in 1967, “poor people have been much more discreet about their starving.” But his work also met criticism. One review called his account of the late Democrat senator Edward M. Kennedy of Massachusetts and the 1969 Chappaquiddick incident a “slander book.”

Sherrill had little patience for the decorum of the political press corps. As a reporter for the Miami Herald in 1964, he punched a press aide to C. Farris Bryant, the Democratic governor of Florida, while aboard a campaign train for Johnson, the Democratic presidential incumbent. “I may have messed up a guy’s jaw, but it wasn’t a big deal,” Sherrill would later tell the Atlantic Weekly.

The truculent journalist moved to the nation’s capital in 1965 and soon became White House correspondent for the Nation, his tenure distinguished by the fact that he lacked access to the White House. His application for a press pass was denied in 1966.

The Secret Service, after an investigation, determined that he was not eligible, and addressed a memorandum to Bill Moyers, Johnson’s press secretary at the time, asking that the information on which the agency’s conclusion was based “not be disclosed to Mr. Sherrill or his employer,” as later recounted in the D.C. Circuit opinion.

As the ACLU took up his case, the White House confirmed that the reporter had been denied accreditation “for reasons of security.” A Treasury official informed the reporter that his arrest for physical assault in Florida was at issue.

The ACLU filed a complaint on the reporter’s behalf in district court, alleging breach of the First and Fifth amendments, which guarantee freedom of the press and due process of law. Rather than deciding on the legality of the denial itself, the court instructed the Secret Service to “devise and publicize narrow and specific standards” for refusing access.

A three-judge panel of the appeals court — Carl E. McGowan, Harold Leventhal and Roger Robb — affirmed that judgment, with McGowan writing for the panel. While acknowledging that “a citizen’s right to obtain information” is limited, the appeals court reasoned that the “First Amendment interest” was significant enough to set clear “requirements of notice” when shutting out a journalist.

Fundamentally, the court found that the First Amendment protected press access to the White House.

“White House press facilities having been made publicly available as a source of information for newsmen, the protection afforded newsgathering under the First Amendment guarantee of freedom of the press requires that this access not be denied arbitrarily or for less than compelling reasons,” the appeals court reasoned.

The physical safety of the president might very well be a legitimate reason, the court argued, but it had to be made publicly known and subject to rebuttal. The court further judged that “arbitrary or content-based criteria for press pass issuance are prohibited under the First Amendment.”

Luke M. Milligan, a professor at the University of Louisville School of Law and author of a law review article on press rights, told The Post in an email that it will be difficult for CNN to prove that the content of Acosta’s reporting was cause for the denial, while the White House “will point to the journalist’s disruptive conduct — not yielding to other reporters, refusing to hand over the microphone and lecturing the president rather than asking a question.”

But Josh Blackman of the South Texas College of Law in Houston said a court doesn’t need to decide that “President Trump’s hatred of CNN renders the denial unconstitutional.” The network gave a court the opportunity to avoid ruling on a thorny constitutional question by pairing its First Amendment argument with a claim that the denial was “arbitrary and capricious,” in violation of the Administrative Procedure Act.

“If a court is inclined to think the administration violated the First Amendment, the judge is also likely to think the denial is ‘arbitrary and capricious,’ ” Blackman said. “Therefore, the remedy would be to restore the press pass.”

Acosta’s case has implications beyond his high-profile feud with the president. As the Reporters Committee for Freedom of the Press observed in a brief, “All members of the news media feel the threat to First Amendment freedoms posed by the government’s retaliatory revocation of Acosta’s security credentials — a threat made all the more real by President Trump’s promise that there ‘could be others’ who also lose their White House security credentials.”

But if Sherrill’s case suggests that the government’s approach is on infirm footing, the reporter’s approach offers lessons, too.

Though he won his case against the Secret Service, he didn’t go running for credentials.

“The fun thing about this was that when I was finally going to get a press pass, I never applied,” Sherrill told the Los Angeles Times in 1990. “I didn’t want to be in the White House. I had been in Washington long enough to realize that was the last place to waste your time sitting around for some dumb . . . to give a press conference."

Sherrill died in 2014 at the age of 89.