By now the facts are well-known: Trayvon Martin was a 17-year-old young black man who, on Feb. 26, 2012, was walking home from a 7-Eleven in Sanford, Florida, with a bag of Skittles and a bottle of iced tea. George Zimmerman, a neighborhood watchman of white and Latino heritage, though advised by police not to pursue Trayvon himself, got out of his car carrying his 9-millimeter handgun. Allegedly after some confrontation, Zimmerman shot Trayvon dead.

Should we think about this horrendous incident as a random encounter, or does it teach us something about the politics of race and the persistence of racial bias in America today?

When Zimmerman first called the police about Trayvon Martin, he said: “There’s a real suspicious guy. This guy looks like he’s up to no good, on drugs or something. It’s raining, and he’s just walking around looking about.” Writer E.J. Graff termed this “Walking While Black.” In other words, Trayvon was presumed to be guilty of something nefarious simply because of the color of his skin.

Some who’ve listened to the tape of Zimmerman’s 911 call believe they heard him use an obscenity and a racial slur. But whether Zimmerman is an overt racist or not is largely beside the point. Focusing on relatively isolated instances of overt racism tends to obscure and excuse the very pernicious, very persistent reality of implicit racial bias that runs throughout our society — and very much shaped how the world saw Trayvon Martin and how the world sees President Obama still.

Most people don’t throw around racial epithets, let alone admit they do so to researchers. Yet we know that racial stereotypes still exist in America, leading scientists now to focus on implicit bias: unconscious mental shortcuts that we form based on our life experience as well as the stories, culture and history we absorb around us.

In one study, researchers used computers to generate several faces that were exactly the same except for the skin color — half were black and half were white. All respondents (yes, including black people studied for the project) were more likely to rate the black faces as showing greater hostility. In another study, scientists showed a group of subjects a video of one person pushing another person. When the “shover” was black and the “victim” was white, 75 percent of research subjects said the push was aggressive. When the “shover” was white and the victim was “black,” only 17 percent of subjects said the push was aggressive.

Implicit racial bias has also been found in what researchers call a “shooter bias” — in which subjects playing a simulated video game are more likely to mistakenly pull the trigger on unarmed black men than on unarmed white suspects. The phenomenon has been tested and proved with police officers, too.

Watching conservative attacks on Obama, it’s hard not to conclude that they are tainted by implicit bias. Consider: President Barack Obama is the first African-American president of the United States of America. From day one, conservatives have attacked the president’s religion, citizenship and essential patriotism. Conservatives condemned healthcare reform in general and the individual mandate in particular, even though the mandate was originally a Republican proposal. Republicans, who historically never met a tax cut they didn’t like, have opposed virtually every tax cut proposal that President Obama has put forth. Amidst high unemployment and a crumbling economy, Republican Senate Minority Leader Mitch McConnell said his number one goal was to destroy the president’s chance for re-election.

Now, I do not believe that Mitch McConnell or most Republican leaders or rank-and-file voters are overt racists. But their rhetoric often evokes the same racial animus that Zimmerman seems to have expressed. Republican presidential candidate Newt Gingrich has labeled President Obama “the most dangerous president in history.” Glenn Beck once accused President Obama of having a “deep-seated hatred of white people.” And long before he called Sandra Fluke a slut, conservative mascot Rush Limbaugh said: “Obama is an angry black guy.” The parallel imagery is clear: President Obama, like Trayvon Williams, is a dangerous, suspicious black man clearly up to no good, guilty of Governing While Black.

And implicit bias has been tested with respect to President Obama. Researchers have shown that those with high rates of implicit racial bias were not only less likely to vote for President Obama but less likely to support his healthcare reform proposal. In fact, researchers were able to demonstrate that subjects were more supportive of the exact same healthcare reform proposals if they were ascribed to President Bill Clinton as opposed to President Obama.

In his book The Trouble With Black Boys, New York University professor of education Pedro Noguera writes:

Unlike men and women from other racial and ethnic groups, Black males are rarely seen as individuals in possession of a full range of attributes and flaws, strengths and weaknesses. The stereotypes that shape the American images of Black males are so stark and extreme that even the most ordinary and unexceptional Black males find they are forced to contend with the fantasies and fears that others hold toward them.

Trayvon Martin had a handful of Skittles. Barack Obama holds the presidential pen. But both are viewed, especially by white America, as holding weapons, and in my view, both have been mistakenly fired upon, whether with real bullets or unprecedented political vitriol.

PHOTO: An undated handout photo released by the Martin family’s public relations representative shows 17-year-old Trayvon Martin. REUTERS/Handout