William Carlos Williams was recovering from a stroke at his home in Rutherford, New Jersey, when the phone rang.

A federal agent was on the line.

Williams, by then 71 years old, was a local doctor credited with delivering more than 3,000 babies. On the side, he'd managed to become one of the 20th century's most revered poets, gaining critical acclaim for inventive verse that blew up the conventions of American poetry and spoke to the nation in its own, peculiar voice.

Decades later, his work would become mainstream, appearing in classroom textbooks, inspiring artwork and films such as 2016's "Paterson" and prompting loving parodies of his most famous poems, "This Is Just to Say" and "The Red Wheelbarrow."

But this was September 1954, and Williams was under a cloud of suspicion.

Two years earlier, the Federal Bureau of Investigation opened an inquiry into his loyalty to the United States.

The agent, Donald Hostetter, was calling about articles in Washington newspapers detailing the minor scandal that surrounded the probe.

The papers reported the so-called loyalty investigation, which concerned the poet's alleged communist ties, had derailed the naming of Williams as Consultant in Poetry to the Library of Congress, a coveted position that later became known as Poet Laureate of the United States.

The agent's issue was that the stories suggested the FBI had been too slow in wrapping up its inquiry. His bosses at the bureau wanted answers.

Williams was "cordial," the agent later noted in a memo, but he'd been ill, and the investigation had sent the poet into such a deep depression that he'd done a stint in a psychiatric hospital. He had little patience for the federal government.

The men scheduled a date to meet in person, but Williams never kept the appointment. His family was worried a meeting with the FBI would make his condition worse, records show. So, he had a lawyer phone the agent, instead.

Though named, Williams never served as poet laureate and the FBI never formally released its findings.

The controversy, which drew puzzled national press coverage at the time, has since faded from history, save for a few passages in biographies and academic papers dissecting Williams' work.

But the poet's FBI file, requested for this story last year under the federal Freedom of Information Act, provides little-known details about the investigation, which was sparked by the bureau's now-infamous director, J. Edgar Hoover, after Williams was attacked by an anti-communist newspaper in September 1952.

The inquiry didn't turn up much before it was halted as the library cowed to political pressure, hiding behind the poet's illness. Williams, meanwhile, was left in the dark for more than two years.

"I don't know a thing," Williams told a Washington newspaper days before the FBI agent called him. "What did they find? They never did give me any indication. I received a communication from the FBI to be fingerprinted and replied to all sorts of preliminary inquiries. Then I wasn't even given the courtesy of a reply.

"For heaven's sake, what kind of a country is this?"

The records show FBI investigators found the good doctor signed petitions, spoke at a few lefty rallies in favor of civil liberties and, like a lot of artists, had some friends whose views could charitably be described as kooky.

They also found few detractors -- outside columnists and commentators in the right-wing press -- who saw the poet's appointment as a cudgel they could use to attack the Library of Congress over its taxpayer-subsidized support of artists.

Most of the FBI documents were declassified in the 1980s. Some were made public for the first time just last year.

They reveal how one of America's most revered poets got swept up in a wave of anti-communist rhetoric, carried along by a federal investigation that went nowhere and was unceremoniously dumped into a kind of Washington purgatory, where a collection of bureaucrats refused for years to either reject him or clear his name.

THE LOYALTY ORDER

Williams expected it to be "the crowning gesture of my life as a literary man."

He had published "Paterson" -- his book-length, epic poem about New Jersey's third-largest city, its people and its majestic Great Falls -- just two years earlier, earning the National Book Award in 1950. Then, on Aug. 8, 1952, the Library of Congress announced it had chosen him for its top poetry post.

But Williams had been in poor health, having recently suffered the first of a series of strokes.

His wife, Flossie, wrote to the Library, requesting his appointment be delayed until mid-December while her husband recovered. Meanwhile, the couple prepared to leave New Jersey, renting a house on Capitol Hill.

J. Edgar Hoover had other ideas.

On Oct. 9, 1952, the FBI director sent a memo to James Hatcher, the chief of the bureau's Investigation Division, raising concerns over Williams' mention in the Sept. 17 issue of Counterattack, a right-wing anti-communist newspaper best known for publishing the pamphlet "Red Channels," which outed entertainers believed to have communist sympathies.

The article drew attention to a laundry list of petitions and letters Williams had signed, connecting him to "leading Communists and fellow travelers."

"Can't (the) Library of Congress find a distinguished poet with a pro-freedom record to fill the post?" the authors asked. "As long as U.S. Gov't is subsidizing people, why doesn't it subsidize anti-totalitarians?"

Hoover's memo asked Hatcher to look into whether Williams' poetry position fell under Executive Order 9835. Known as the "Loyalty Order," the 1947 directive signed by President Harry S. Truman was meant to root out communist sympathizers in the federal government. Now considered an early step in the second Red Scare following World War II, it gave the FBI the power to run preliminary background checks on any federal employee and follow up with a detailed inquiry if anything seemed amiss.

On Oct. 27, the Library's director of personnel, J.H. Mason, wrote to Hatcher that his office was aware of Hoover's memo and was requesting "a full field investigation of this individual."

It wasn't the first time William Carlos Williams drew the attention of the FBI.

The FBI Encyclopedia, a 400-page reference guide on the history of the bureau, contains a five-paragraph entry on the poet.

It notes he first fell under its radar in 1930, when Williams wrote a letter to the magazine New Masses, praising a piece by the radical journalist John Reed. He again caught their eye in 1943, when his good friend and fellow poet Ezra Pound was accused of treason for producing radio broadcasts transmitted from Italy criticizing the American government during the war.

However, Williams -- by most credible accounts -- was never a communist.

In his biography of the poet, "A New World Naked," Paul Mariani writes that Williams "saw himself as an American Democrat and a liberal and a virulent anti-Fascist," albeit one who was "at heart apolitical."

But the Library of Congress post brought a new level of scrutiny.

The FBI Encyclopedia says bureau sources leaked details of its inquiry to the conservative commentator Fulton Lewis Jr., a firebrand radio host and syndicated newspaper columnist. In a November 1952 column, which found its way into the FBI's records, Lewis also revealed that the House Un-American Activities Committee had a file on Williams containing "50 cards, listing his association with some of the smelly outfits that have been peddling Moscow propaganda in the U.S. for 25 years."

Yet, when FBI agents interviewed Williams' associates, they found little to suggest he was a subversive. Records show over the course of several weeks, they spoke to a series of friends and associates -- from the police chief in his hometown of Rutherford to the academics who invited Williams to address their classes.

All of them called Williams a loyal American, the FBI's file shows.

Sculley Bradley, an acquaintance and English professor at the University of Pennsylvania, told an investigator Williams "could be considered 'radical' only in that his literary form was different," according to the agent's memo.

THE INVESTIGATION THAT WENT NOWHERE

Still, Williams was quickly becoming a political problem for the Library of Congress.

In January 1953, the federal Civil Service Commission, a government employment agency, asked the FBI to drop its inquiry into Williams, indicating his nomination had been rescinded.

For decades after, it remained unclear whether the post was revoked because of the loyalty investigation or due to Williams' health, which deteriorated further during the course of the probe.

Williams had hired an attorney, New Jersey lawmaker James F. Murray Jr., to represent him in the inquiry and library officials took umbrage at the poet lawyering up, at one point claiming that was why they rescinded his nomination.

The poet, for his part, wanted to clear his name.

Murray demanded the Library of Congress ask the FBI to reopen its investigation and complete its report, records show. But turnover among the leadership at the library only caused further delays, and while the investigation was briefly reopened, the matter was never formally resolved.

Mariani's biography of Williams notes that in October 1954, a letter from a top Library of Congress official was published in The New York Times indicating the investigation raised no doubts about his loyalty to the United States.

Yet, the FBI documents now show a memo to Hoover from the Civil Service Commission sent just a month later, on Nov. 22, 1954, stated that the poet's appointment was rejected "because of (an) unfavorable report," suggesting the loyalty probe did, in fact, derail Williams' selection.

The ordeal created the longest vacancy in the history of the United States' poet laureate program. And by the time the poet and literary critic Randall Jarrell was named to the post in March 1956, FBI records indicate, Hoover was still keenly interested in appointments to the position.

After an article about Jarrell's nomination appeared in The Washington Post, Hoover again asked his agents to look into Williams' situation, according to FBI records. They produced a series of memos defending the loyalty investigation and pinning the blame for the Williams controversy on the Library of Congress' administrative bungling.

But the FBI didn't get out of the business of vetting the political leanings of poets.

Hoover, one memo said, wanted "to see the memorandum concerning the investigation on Williams and also asked if we have anything on Randall Jarrell."

WANT TO READ MORE? WE'VE POSTED WILLIAMS' FBI FILE HERE.

S.P. Sullivan may be reached at ssullivan@njadvancemedia.com. Follow him on Twitter. Find NJ.com on Facebook.