John A. Stormer, a Cold War-era anti-communist author and pastor whose widely circulated book “None Dare Call It Treason” warned of Soviet subversion in America and helped catapult arch-conservative standardbearer Barry Goldwater to the Republican presidential nomination in 1964, died July 10 at a rehabilitation center in Troy, Mo. He was 90.

A spokeswoman for McCoy-Blossom Funeral Home in Troy confirmed the death, which was announced on its web site. No cause was provided.

With the Soviet Union already in open control of a quarter of the world’s land mass, including Cuba, Mr. Stormer wrote in his treatise, “The hidden tentacles of the communist conspiracy exert unmeasured influence over the rest of the world.”

Mr. Stormer flooded the country with 7 million copies of his 75-cent, self-published paperback with the help of a few deep-pocketed Republican donors in the first 10 months of 1964. The red-baiting volume helped consolidate some of Goldwater’s far-right base and made the two-term Arizona senator the clear front-runner for the GOP nomination against more moderate candidates.

Goldwater was praised throughout “None Dare Call It Treason” for touting a tough military stance against Soviet expansionism abroad and warning against Communist-stoked “federal paternalism” at home — the war cry of a new Republican conservatism in the wake of the more centrist Eisenhower administration of the 1950s.

Mr. Stormer cast the Eisenhower administration’s trade agreements and nuclear test ban talks with the Soviets as “accommodation” and “concessions” in “a continual erosion of the American position.” He agreed with the John Birch Society and other far-right groups that the State Department was honeycombed with communists and elite leftist intellectual sympathizers bent on the destruction of American democracy — a conspiratorial legacy of Wisconsin Republican Sen. Joseph R. McCarthy’s anti-communist witch hunt of the early 1950s.

“Lenin and his heirs have had the sometimes knowing, sometimes unknowing, cooperation of the United States State Department every step of the way,” Mr. Stormer wrote.

More broadly, he described what he saw as the gradual undermining of traditional values of American churches, schools, civic organizations and, ultimately, the government — a slow-cooked scheme of wealth redistribution, welfarism and nanny-state rules, sapping Americans of their sense of initiative and personal responsibility.

“Extremism in the defense of liberty is no vice,” Goldwater declared at the Republican National Convention, adding “moderation in the pursuit of justice is no virtue.”

It was the sort of battle cry that worried moderates in the party but delighted his Democratic opponent, incumbent President Lyndon B. Johnson, whose surrogates painted Goldwater as unhinged and likely to trigger a nuclear war.

The infamous “Daisy” ad on television, in which the image of a young girl plucking daisy petals mutates into a nuclear countdown and mushroom cloud, played into those fears of a Goldwater presidency and the influence held by the Birchers and hawkish authors such as Mr. Stormer, who chaired his Missouri congressional district’s pro-Goldwater committee.

The daisy commercial, which aired only once but was shown repeatedly on newscasts, was credited with helping Johnson win the election in a landslide. Mr. Stormer and other Republicans claimed his book’s power was lasting and helped fuel a rise of a new, more aggressive GOP conservatism that brought Ronald Reagan to the White House in 1981.

Mr. Stormer’s theories of a hydra-headed plot became emblematic of what historian Richard Hofstadter called the “paranoid style in American politics” — a phenomenon occurring periodically throughout American history. It involved, Hofstadter wrote in 1964, a belief in “the existence of a vast, insidious, preternaturally effective international conspiratorial network designed to perpetrate acts of the most fiendish character.”

Writing in Politico in 2010, scholar Matthew Dallek made a direct link between Mr. Stormer’s book and later conspiracy-minded extremists such as broadcaster Glenn Beck who feed into “this sense of a nation besieged by liberals. They seem to see themselves in a struggle in which violence may be justified to defend the nation’s revolutionary heritage.”

Mr. Stormer’s book contained more than 800 footnotes in its 253 pages, documenting his claims of Marxist infiltration with citations from government studies, newspaper articles and congressional committee reports.

Despite the patina of scholarship, the book encountered heavy criticism. Several moderate Republican leaders questioned its more sweeping conspiracist notions. And in September 1964, two months before the presidential election, a nonpartisan citizens group called the National Committee for Civic Responsibility placed a report in the Congressional Record blasting the book in a withering page-by-page critique.

“At best,” it said, the book was “an incredibly poor job of research and documentation and, at worst, a deliberate hoax and a fraud.”

The book cited a 1934 letter by labor leaders Walter and Victor Reuther that said, “Carry on the fight for a Soviet America” — an established hoax with six different versions, according to additional research reported by the New York Times in 2017.

Nevertheless, the book and two other ultraconservative, self-published paperbacks — Phyllis Schlafly’s “A Choice Not an Echo” and J. Evetts Haley’s “A Texan Looks at Lyndon” — were distributed by the millions throughout the campaign season, often sold at discount or given away.

The mass distribution marked a unique publicity initiative by the Republican right in which it largely ignored both the mainstream media and standard GOP publications of the day, such as National Review and Human Events. The sudden flood of privately circulated paperbacks by little-known authors without the imprimatur of established book-publishing companies “energized grassroots conservatives, helped Barry Goldwater secure the GOP nomination, and framed the right’s alternative campaign,” Nicole Hemmer, author of “Messengers of the Right: Conservative Media and the Transformation of American Politics,” wrote in the Atlantic Online in 2014.

The Goldwaterites, Hemmer wrote, “harbored deep suspicions” of the national media and distrusted the GOP establishment that tended to support Goldwater’s more moderate competitors for the nomination, Pennsylvania Gov. William W. Scranton and New York Gov. Nelson A. Rockefeller.

In their alternative gambit, Goldwater backers skipped the established book-distribution system for their own grass-roots blitz, blanketing much of the nation indiscriminately but also targeting key Republican strategists as well as delegates to the GOP national convention in San Francisco in July 1964. Several wealthy conservative backers, including Texas oil tycoon H.L. Hunt, helped bankroll the campaign.

It was a crucial moment in conservative media activism, noted Hemmer, in which “unknown grassroots activists intersect with powerful right-wing distribution networks. The role these books played in the Goldwater nomination drive show just how powerful such moments can be.”

John Anthony Stormer, a plumber’s son, was born in Altoona, Pa., on Feb. 9, 1928. He attended Pennsylvania State University in the late 1940s, then joined the Air Force during the Korean War and served as a historian.

He graduated in 1954 from San Jose State College (now University) in California and spent the next several years working for Volt-Age, an electrical industry magazine, rising to editor and general manager. He became a follower of American missionary and early anti-communist activist George S. Benson.

A religious fundamentalist, Mr. Stormer joined the Heritage Baptist Church in Florissant, Mo., a suburb of St. Louis, and served as pastor for decades. He also headed the nearby Faith Christian School and spent a decade as president of the Missouri Association of Christian Schools.

Using both the pulpit and articles featured in the Christian Beacon, a weekly newspaper published by nationally known fundamentalist Carl McIntire, Mr. Stormer built a substantial public following. He was a fixture in Missouri’s Republican Party, speaking frequently at political functions and conducting weekly Bible studies for members of the state legislature.

In 1963, he founded his own publishing house, Liberty Bell Press, from which sprang “None Dare Call It Treason” and six other related books that followed over the next four decades, including “None Dare Call It Education: What’s Happening to Our Schools and Our Children?” (1998).

Mr. Stormer married Elizabeth Lewis in 1951. In addition to his wife, survivors include a daughter, Holly Hartzell; a sister; four grandchildren; and nine great-grandchildren, according to his death notice.

The collapse of the Soviet Union in 1991 did not blunt Mr. Stormer’s concern about spreading communism. He said front groups in America and elsewhere continued to promote a subversive, pro-communist agenda.

In an interview on America’s Survival TV in December 2014, he cited claims by police of communist-instigated protests in the wake of the police shooting in Ferguson, Mo., of Michael Brown on Aug. 9, 2014. “There were hundreds of people from all over the country put in hotels and organized those protests,” he said.

They were, he added, “looking ultimately to bring about revolution.”