When you write a book, particularly one that requires several years of research, you tend to encounter a bunch of unexpected information. Sometimes you find things that, if reported, will undoubtedly prompt partisans to demand you explain yourself. For me, this begins that process of explaining, given that one of the major characters in my new book on American Communists, Dupes, is Frank Marshall Davis.

Allegations regarding Davis’s Communism are sure to infuriate the Left because of the influence Davis once had over our president. He was a drinking buddy of Barack Obama’s maternal grandfather, Stanley Dunham, and spent time with young Obama. He turns up in the president’s memoir, Dreams from My Father, shrewdly identified only as “Frank”: “I was intrigued by old Frank, with his books and whiskey breath and the hint of hard-earned knowledge behind the hooded eyes.” Recently, a U.S. Communist-party official confirmed the relationship, bragging in a speech of the Communist Davis’s formative influence over Obama. And yet when the allegations surfaced during the 2008 campaign, they went virtually unreported in the mainstream media.

After an almost four-year-long sojourn in which I tried to ascertain whether Davis was a progressive duped by Communists, or, conversely, a Communist who duped progressives, I determined the latter. No doubt, this conclusion — which means the leader of the free world was strongly influenced by a Marxist — will bring the unholy wrath of liberals. Yet, they should brace themselves for another kind of anger. Once they read what Davis did and wrote, they might redirect their rage. In truth, Davis’s targets were mainly Democrats, and especially a Democratic icon, Harry Truman. What Davis said about Truman was unbelievably outrageous. Worse, he said it because it was the Moscow line.

Since the early 1990s, I’ve been absorbed with archives from the Soviet and Communist world — I’ve looked at every kind of declassified holding. In recent years, I’ve concentrated on an extraordinary cache of material from the Comintern Archives on Communist Party USA (CPUSA). This material is utterly damning to the American Left, especially in its vindication of the worst fears and warnings of anti-Communists. Not surprisingly, our illustrious “scholars” in the academy are studiously ignoring it.

When I heard the accusations that Davis was both a Communist and a former mentor of Obama’s, I began noticing his name in documents, from House and Senate investigations to materials for hideous Communist fronts such as the American Peace Mobilization, a group that supported or opposed Hitler based entirely on whether he was signing non-aggression pacts with Stalin’s USSR or invading Stalin’s USSR. This group also unrelentingly demonized Franklin Delano Roosevelt.

I learned that Davis served as an editor and writer for a Communist-line publication, the Chicago Star, in the 1930s. I next learned that the Midwest native had flown thousands of miles away to Hawaii to take up permanent residence, just when American Communists were looking to launch a publication there, namely the Honolulu Record. Subsequently, Davis wrote a weekly column for that publication.

With the help of two super-impressive researchers, including one living in Hawaii, I procured Davis’s weekly “Frank-ly Speaking” columns for the Record. These writings flawlessly parroted official Soviet propaganda and portrayed the likes of Harry Truman, George Marshall, and other courageous Democrats as colonialist-imperialist-fascist-racist monsters. Davis even denounced the Marshall Plan. As any student of this era knows, only the Soviet Union, via the public voices of Stalin and Molotov, took this absurd position.

In column after column, Davis claimed Truman craved not only a “third world war,” but to “rule Russia.” Davis said that Truman’s “fascism, American style” was motivated by an anti-Communism that was fueled by veiled racism. Davis repeatedly asserted that the Soviet Union not only desired peace — as Stalin seized Eastern Europe, while also killing tens of millions of his own people — but had abolished poverty, unemployment, and even racism.

Such examples from Davis are so voluminous that they constitute the longest chapter in my 600-plus-page book. Summarizing them here is impossible. But here are three telling examples.