LOS ANGELES — It’s a conspiracy: The 2016 campaign features one candidate who warned against the “vast right-wing conspiracy” and another who was a leader of the so-called “birther” movement.

Donald Trump and his surrogates hint at a mysterious “illness” afflicting rival Hillary Clinton. Pushing back, Clinton warns of murky ties between Trump and the Russian government, insinuating that her Republican opponent may be a puppet of Russian President Vladimir Putin.

Rumors and innuendo long confined to the far reaches of the internet are dominating the presidential race, forcing Clinton to grapple — once again — with the kinds of whispers that have dogged her family for decades.

Clinton has largely avoided discussing the conspiracies, leaving it to members of her campaign team or allies. But she is preparing a Reno, Nevada, address today that will accuse Trump of supporting an “alt-right” campaign that presents “a divisive and dystopian view of America.”

“I do feel sometimes like this campaign has entered into an alternative universe,” Clinton said in an appearance Monday night on ABC’s “Jimmy Kimmel Live.”

She described Trump Wednesday night on CNN as a candidate who is campaigning on anger and hatred.

“Donald Trump has shown us who he is and we ought to believe him,” she said. “He is taking a hate movement mainstream. He has brought it into his campaign. He’s bringing it to our communities and our country.”

Driven by big personalities, the 2016 election has become a perfect storm for conspiracy theories. Clinton famously called her husband’s opponents part of a “vast right-wing conspiracy” and her family has long been central to a cottage industry of sordid tales about her husband and family.

Trump is known for peddling conspiracies and was at the center of the “birther” movement that questioned whether President Barack Obama was born in the United States (Obama was born in Hawaii). Trump, a businessman and reality TV star, has frequently tossed out rumors about Clinton’s health and sleep schedule on the stump and on Twitter, aiming to discredit her fitness for office.

Sensing an opportunity, Clinton’s team seized upon the rumor-mongering after the GOP nominee plucked Steve Bannon, the executive chairman of the conservative website Breitbart News, to be his new campaign chairman this month.

They highlight that Trump has been informally advised by Roger Ailes, the former chairman and CEO of Fox News, which has aired segments questioning Clinton’s health, and GOP consultant Roger Stone, who has pushed politically loaded innuendo about the Clintons for years.

Clinton, who turns 69 in late October, is younger than the 70-year-old Trump. But her health has remained front-and-center.

Much of the speculation stems from a concussion Clinton sustained in December 2012 after fainting in her final weeks as secretary of state, an episode her doctor has attributed to a stomach virus and dehydration.

During the course of her treatment, she was found to have a blood clot in a vein in the space between the brain and the skull behind the right ear. To recover, Clinton spent a few days at a hospital and took a month-long absence from the State Department for treatment.

Republican strategist Karl Rove later cast the incident as a “serious health episode” that would be an issue if Clinton ran for president, fueling a theory the concussion posed a graver threat to her abilities than Clinton and her team let on.

Former New York Mayor Rudy Giuliani, a top Trump surrogate, urged voters to “go online and put down ‘Hillary Clinton illness,”’ in a Sunday interview with Fox News. And Trump has repeatedly questioned her stamina at campaign rallies.

“She gives a short speech then she goes home, goes to sleep, she shows up two days later. Remember, short circuit. Remember that, right? Short circuit,” he said at a Florida rally earlier this month.

When the accusations made their way into a recent Trump foreign policy address, in which he said she “lacks the mental and physical stamina” to fight Islamic State militants, Clinton’s campaign felt they had to respond.

Her team put out a statement from Dr. Lisa Bardack, an internist who proclaimed Clinton in “excellent physical condition and fit to serve as president of the United States.” Bardack had said in 2013 that testing showed “complete resolution” of the concussion’s effects, including double vision, which had led Clinton to wear glasses with special lenses, further fueling rumors.

Fanned by right-wing media sites, like Breitbart, the rumors occasionally break through onto cable news and other mainstream media.

In the aftermath of hacked Democratic emails, Trump encouraged hackers from Russia to find Clinton’s missing State Department emails, an apparent invitation for a foreign power to intervene in a U.S. election.

Clinton’s team frequently points to Trump’s ties to Russia. Her campaign has a page on its website devoted to a Q-and-A about Trump’s “bizarre relationship” with Russia, fueling an unproven theory that Trump is a shill for Putin.