Three years later, Coughlin took over a small congregation in the Royal Oak suburb of Detroit, and promptly built a new church. Deeply in debt to the diocese, he tried a variety of ways to raise money for his congregation. Nearing the end of his financial tether, he agreed to broadcast his sermons on WJR, a local station that was in equally dire straits.

Reading Coughlin’s sermons at a remove of eighty years, it’s difficult to see what all the fuss was about. His prose is stilted, repetitious, a bit leaden. But from the beginning Coughlin connected to listeners in an electric way. Part of his appeal, of course, was pure novelty. He was among the first to offer regular religious services over the air, and despite criticism from some within the church, he built the first true radio congregation.

Coughlin was also a master at identifying with the concerns and anxieties of his audience. He was emotional, dramatic, and evocative: the mother of a kidnapped child was having her heart crushed “in a great press, making her bleed the wine of sorrow.” The “purple poison of Bolshevism” was like “a great red serpent” winding its sinews around the American soul. And those who closed their eyes to these mounting dangers dwelled in “the smiling acres of Lotus Land where it is always afternoon, always springtime . . . dulled by the opiate of their own contentedness to such a degree that they possess no prospect of what the future years hold in store for our nation.”

But most of all, there was the voice. The novelist Wallace Stegner described it as a “voice of such mellow richness, such manly, heart-warming confidential intimacy, such emotional and ingratiating charm, that anyone tuning past it almost automatically returned to hear it again.” It was, Stegner wrote, “a voice made for promises.”

Though history now remembers Coughlin as among Roosevelt’s fiercest political foes, they began as close, if uneasy, allies. Having assailed Herbert Hoover and his gang of “international financiers” during the onset of the Great Depression, the priest looked more kindly upon Hoover’s successor. Throughout 1932 and 1933, he lavished fulsome praise upon FDR in his broadcasts and encouraged his listeners to do the same. It was “Roosevelt or ruin,” Coughlin declared on more than one occasion.

Yet Roosevelt remained wary of Coughlin. As he did with Huey Long, another potential threat to his presidency, Roosevelt maintained an outward cordiality with the priest, meeting with him occasionally and directing his staff to reply to the voluminous tips, suggestions, and notes Coughlin communicated to the White House. But Roosevelt’s private papers make clear that he saw the Detroit broadcaster as a demagogue, whom he genuinely disliked.

There was never a single decisive moment that shifted their relationship, but in the year following FDR’s election it became increasingly clear that Coughlin, despite his ratings clout, was not going to be invited into the president’s inner circle. By 1934 the frustrated priest’s ardor for the New Deal cooled, and anti-Roosevelt jibes began to creep into his broadcasts, as did an even more apocalyptic tone.

“Capitalism is doomed and is not worth trying to save,” he exhorted the flock in February 1934, calling it a “Siamese twin” of Marxist socialism. In November of that year, Coughlin announced he was forming a new group called the National Union for Social Justice. This independent organization would be based upon “16 Principles” identified by its founder—including abolition of the Federal Reserve, simplification of government, and liberty of conscience. The aim of the group, said Coughlin, was to “drive out of public life” those who had betrayed these principles and broken their promises to the people. He boasted that the union would soon recruit five million members.

Coughlin’s first opportunity to flex his new political muscle came just a few months later. In January 1935, Roosevelt sent a long-delayed treaty to the heavily Democratic Senate, which would make the United States a participant in the World Court. The administration was confident of gaining ratification. Less than forty-eight hours before the vote, however, Coughlin took to the air to denounce the treaty as an affront to American sovereignty. In a voice filled with manly indignation, he urged his listeners to “keep America safe for Americans and not the hunting grounds for international plutocrats!”

Within hours of Coughlin’s broadcast, tens of thousands of telegrams flooded the Senate, and the treaty was rejected by a wide margin. “I regard this a decisive defeat of the administration,” Harold Ickes, Roosevelt’s Secretary of the Interior, recorded in his diary of the vote. One Democratic party official warned that Coughlin had become “a bigger menace to the President and our government than ever.” The Fighting Priest, of course, was jubilant.

Douglas McCollam is a contributing editor to CJR.