When Rudy Giuliani dared to name Frank Marshall Davis (Communist Party card no. 47544) as an influence on a young Obama, liberals ripped their garments and wailed “blasphemy!” Rudy’s unpardonable sin reminded them of all sorts of noxious behavior. And in some cases, it reminded liberals of -- what else? -- racism.

“This week’s race to the bottom, led by former New York City Mayor Rudy Giuliani, is proving why Americans are learning to hate politics and the media,” stated Chuck Todd on NBC’s “Meet the Press.” “Giuliani even used an old racial dog whistle of the Civil Rights era, communism.”

To illustrate Rudy’s effrontery, Todd played a clip of this blatant display of racism: “[Obama’s] grandfather introduced him to Frank Marshall Davis,” said Rudy, “who was a communist.”

Can you imagine? Have you ever seen such transparent race-baiting? There Rudy was, blowing that “old racial dog whistle of the Civil Rights era, communism.”

For those appalled that liberals would equate anti-communism -- actually, truth-telling about a genuine communist influence on Obama -- with racism, you should know that this is nothing new. Frank Marshall Davis himself mastered the tactic. Ironically, Davis did so counting on non-communist liberals (the communists called them dupes) to join the chorus, screaming “racism” at those who dared point out the work of communists.

But equally intriguing, Barack Obama himself might have alluded to this in his Selma speech.

Before considering Obama and Selma, I’d like to first illustrate how Davis used this insidious form of communist race card. It’s quite revealing.

In reply to accusations of his pro-Soviet/pro-communist work, Frank Marshall Davis regularly charged accusers of being motivated by racism. He did this in his many columns for the Party-line organ in Chicago, the Chicago Star, of which he was the founding editor-in-chief. He continued the tactic in his columns for the Honolulu Record. From 1949-50, Davis used the word “racist” 10 times in his Record columns. In almost every case, the charges were used to denounce anti-Soviet and anti-communist positions. They were leveled at Harry Truman’s foreign policy; at Truman’s attorney general Tom Clark, who sought out communist subversives; at Southern Democrats on the House Committee on Un-American Activities tasked with investigating Americans who swore a loyalty oath to Stalin.

Davis especially smeared Harry Truman. It didn’t matter that Truman did many anti-racist things, such as desegregating the armed forces. For Davis, Truman’s anti-Sovietism was reason to take him down. Davis titled one of his newspaper articles, “White house to white hoods: KKK hails Truman’s policy as its own.”

In his November 24, 1949 Honolulu Record column, Davis explicitly linked anti-communism to KKK membership. “For many years the Ku Klux Klan has been virtually inactive,” wrote Davis. “But recently the groups have come alive… They are trying at present to unite all under a single leadership with the slogan of ‘Fight Communism to Maintain White Supremacy.’… To reaction, any attempt to change the status quo of discrimination is Communistic.”

That Davis was employing this angle to protect himself was obvious. “[I]f you fight too hard for civil rights,” he wrote two weeks later, in a December 8 piece, “you are likely to be branded a communist.” He implied that this was why he was being branded with the “c” word. “I, personally, have no intention of letting the cry of ‘communism’ sidetrack me from my goal of complete civil rights as guaranteed by the Constitution.”

This was a maneuver by Davis to shield not merely himself but other African-American communists suspected (rightly) of being communists -- men like Ben Davis, Henry Winston, and the singing, gushing Stalinist, Paul Robeson. “Negro Americans are concerned about the growing attacks upon their rights, but they are also anxious about the growing assaults upon the liberties of many other groups,” Davis wrote in another column. “Anyone who dares to think for himself and to say what he thinks is in danger of being fired from his job, branded as a Communist subversive, and thrown in jail.”

That was hardly the case with Winston and Ben Davis, who for decades were well-known communists. No one questioned that. Regardless, Frank Marshall Davis protested, “There is no hope for Negro freedom if the liberties of our country are now snuffed out behind anti-Communist hysteria.”

Anti-communism, by this narrative, was destroying the rights of black Americans.

As transparently phony as this defense was, it has been picked up by Frank Marshall Davis’s defenders today. When Davis is mentioned in sympathetic Obama biographies -- or by the likes of Chuck Todd -- he is upheld as a civil-rights crusader who was hounded by merciless anti-communists.

With all of that said, here’s a compelling thought:

Did Barack Obama learn any of this from Davis during their many meetings together? Davis was an openly bitter man, with these feelings including America, as Obama himself notes in quoting him in Dreams from My Father.

Davis always portrayed himself as an innocent victim. In his own memoirs, he refused a direct admission that he joined the Communist Party. He still wanted people to think that allegations against him were the product of racism. In meeting with a young Obama, he likely would have given that impression of his critics.

Could that have happened? I cannot say for certain.

Nonetheless, consider this fascinating passage from Obama’s Selma statement, where he acknowledges previous fighters for civil rights:

As we commemorate their achievement, we are well-served to remember that at the time of the marches, many in power condemned rather than praised them. Back then, they were called Communists, half-breeds, outside agitators, sexual and moral degenerates, and worse -- everything but the name their parents gave them. Their faith was questioned. Their lives were threatened. Their patriotism was challenged.

Obama was speaking of the civil-rights fighters “who crossed this bridge,” most obviously in Selma, but I think he was clearly referring to civil-rights fighters generally. Was he referring to Frank Marshall Davis?

Davis constantly objected that the claims of his “Soviet Activity in the United States” (the title of the 1957 Senate Judiciary Committee report that publicly identified him as a communist), of him being a communist agitator, were mere smears to stop his patriotic civil-rights work. Obama likely knows that, and Obama would also know (as readers of this website know) that Davis in recent years has been described as a sexual and moral degenerate and worse -- everything from bisexual to a pedophile to Obama’s real father.

So, was Barack Obama in Selma referring to Frank Marshall Davis?

For that matter, was Obama possibly including himself in that passage? Take another close read. Obama has been accused of being a communist, an agitator, and (omnipresent on the internet) even of certain sexual behavior back in Chicago. His faith and patriotism have been questioned.

It’s all quite interesting.

But back to my main focus here: Note the linking of communism with racism. It isn’t new. Frank Marshall Davis himself excelled at the tactic.

So, alas, here we are shocked yet again. We can’t even identify communist influences -- men who joined the Communist Party under Stalin -- without being accused of racism. This is what leftists do. This is their “dog whistle.”

The difficult challenge of exposing painful truths from the communist era continues. As always, the enemy of those truths is the liberal left that still covers for some of the worst agitators of long ago.

Dr. Paul Kengor is professor of political science and executive director of The Center for Vision & Values at Grove City College. His books include The Communist: Frank Marshall Davis, The Untold Story of Barack Obama’s Mentor and Dupes: How America’s Adversaries Have Manipulated Progressives for a Century.