Conspiracy theories about Barack Obama have not gone away in his post-presidency. But they have inspired a new book of fictional short stories that subtly raises an intriguing question: Why are there so many outlandish conspiracy theories about Barack Obama?

Ever since his 2004 debut on the national stage, Obama has attracted bizarre conspiracy claims like honey attracts bears, and unsupported stories have swarmed around Obama’s public image. They began with years of bogus attacks on his Hawaiian birth certificate that helped to launch his successor President Donald Trump.

They percolate today in the fever swamps of fringe media claims that he’s running a “shadow government” from his Washington home to overthrow Trump’s regime and put Democrats back in power.

Remember his uncanny ability to swat flies with his bare hands, which he demonstrated in front of a live network television camera in 2009? (“I got the sucker,” the president famously declared.) A 2013 article in The Atlantic cited that expertly executed act as evidence that Obama might be part of the “reptilian elite,” a long-suspected invasion of alien lizard people.

Yes, The Atlantic’s speculation was tongue-in-cheek, but devoted conspiracy fans in my experience tend to be irony deficient about catching subtle jokes. A 2013 Public Policy Polling survey found 4 percent (or 12.6 million) of Americans believed “lizard people control politics.” Even more, 13 percent (41 million people), thought “Obama is the antichrist.”

Relax, folks. Obama’s not the antichrist and politicians only look like lizard people.

Now the conspiracy theorists have one of their own in the White House. Trump dropped his birth certificate crusade without apology last year only to embrace the idea that an Obama-led plot wiretapped his 2016 campaign. Did he get this information from secret government sources? No, he said, he got it from a Breitbart News story quoting conservative radio host Mark Levin.

Amid this bull market for Obama-related conspiracy theories, it is entirely understandable that a group of writers felt inspired by them enough to produce, “The Obama Inheritance: Fifteen Stories of Conspiracy Noir,” edited by mystery writer Gary Phillips, who also wrote one of the stories.

After all, truth may be stranger than fiction, but why should the conspiracists have all the fun of creating fake narratives?

For example, the first story, “Michelle in Hot Water,” by crime writer Kate Flora, takes on the suspicions, sparked by a fist bump during the 2008 campaign, of the Obamas as secret left-wing black separatists.

The former first lady dons full combat gear and fake skin to lead her band of high-ranking government women into battle to force a greedy pharmaceutical kingpin to lower the cost of cancer-fighting drugs for kids.

In “A Different Frame of Reference,” best-selling mystery writer Walter Mosley turns birther suspicions on their head through a narrator in a white racist organization that tries to trace Barack Obama’s origins — to another planet.

In “True Skin,” by Eric Beetner, even the lizard people make an appearance. Sweet.

Yet, running beneath the book’s mockery of conspiracy fanatics, the unspoken question that I raised earlier persists: Why are there so many outlandish conspiracy theories about the Obamas?

The answer, I believe, can best be detected as this book’s authors do, through the lens of identity — and I’m not talking only about race.

My own shocked reaction to Donald Trump’s widely unexpected election gave me a glimpse of the shock many future Trump supporters must have felt when Obama was elected — twice. The feeling of having one’s world shook up has to be particularly unsettling to conservatives, whose viewpoint is particularly suspicious of change.

Voters care about values more than issues, one of Ronald Reagan’s advisers used to say. The more Obama’s opponents have played up his name and background as exotic, mysterious and threatening, the more fuel is added to their most outlandish fears.

There is a lesson here for the future of American politics. You can tell a lot about a voter by the conspiracy theories he or she believes.

As our electorate has become more diverse and polarized, it has become easier for some voters to regard, say, a gun safety advocate as attacking their cultural tribe, even when they don’t personally own a gun.

Faced with perceived calamities that defy easy explanation, many people find that conspiracy theories provide explanations. Unfortunately, the explanations are usually way too easy for their own good — and everybody else’s.