Donald Trump has indulged in conspiracy theories about President Obama’s birthplace, the FBI’s “rigged” probe of Hillary Clinton, the Federal Reserve’s “political” agenda and whether Ted Cruz’s father was linked to the assassination of John F. Kennedy.

With his presidential campaign in full-blown crisis on Thursday, Trump was at it again, putting a new spin on a familiar tactic.

This time, there was a bigger, badder villain — “a global power structure” of corporate interests, the media and Clinton engaging in subterfuge.

This time, it was about him.

“They knew they would throw every lie they could at me and my family and my loved ones,” said Trump at a rally in West Palm Beach, Fla. “They knew they would stop at nothing to try to stop me. But I never knew, as bad as it would be, I never knew it would be this vile, that it would be this bad, that it would be this vicious.”

In the face of mounting accusations from women that he groped and kissed them without their consent, dozens of media outlets carefully vetting their claims and a Clinton campaign eager to exploit worries about his behavior toward women, Trump decided to lump them together.

“For those who control the levers of power in Washington, and for the global special interests, they partner with these people that don’t have your good in mind. Our campaign represents a true existential threat like they haven’t seen before,” Trump said.

“He is not just talking about Obama’s birth certificate. He is talking about himself,” said Mark Fenster, a University of Florida law professor and author of a 2008 book about conspiracy theories and American culture. “This now becomes a much more personal enterprise about him.”

A day earlier, Trump appeared to allege, without evidence, that House Speaker Paul D. Ryan (Wis.) and other GOP elected officials who distanced themselves from him were involved in a mass scheme to undermine him.

“There’s a whole deal going on — we’re going to figure it out. I always figure things out. But there’s a whole sinister deal going on,” he said.

While spreading information ranging from the questionable to the outright inaccurate with no evidence — a distinctive feature of his campaign — Trump often qualifies his ideas by attributing them to unnamed “people” he claims are speaking about them.

Some of the ideas he has embraced have been denounced by critics who charged that they were racially or culturally derogatory.

Donald Trump strongly denied that he had groped and kissed women without their consent, following a number of news reports detailing allegations made by four women. (The Washington Post)

“.@TeamTrump should avoid rhetoric&tropes that historically have been used ag. Jews & still spur #antisemitism. Lets keep hate out of cmpgn,” Anti-Defamation League chief executive Jonathan Greenblatt tweeted Thursday. He was responding to Trump’s comment that Clinton “meets in secret with international banks to plot the destruction of U.S. sovereignty in order to enrich these global financial powers, her special-interest friends and her donors.”

In his remarks, Trump said “WikiLeaks documents” were evidence of his point. Trump spokesman Steven Cheung said Trump was “talking about Hillary Clinton meeting and speaking to executives at a Brazilian bank, as evidenced by the Wikileaks document dump,” not anti-Semitism.

For years, Trump was at the vanguard of the “birther” movement doubting that Obama was born in the United States despite clear evidence that he was. Only last month did Trump officially put his doubts to rest. In doing so, he falsely blamed Clinton for starting the rumors about Obama.

Last year, Trump said he saw “thousands” of Muslims celebrating in New Jersey as the World Trade Center buildings fell during the Sept. 11, 2001, attacks.

“There were people that were cheering on the other side of New Jersey, where you have large Arab populations. They were cheering as the World Trade Center came down,” Trump said on ABC News in November. “I know it might be not politically correct for you to talk about it, but there were people cheering as that building came down.”

Fact checkers found no evidence to support his claim.

At the end of the Republican primary, Trump said Cruz’s father, Rafael Cruz, was associated with Lee Harvey Oswald around the time he shot Kennedy.

“His father was with Lee Harvey Oswald prior to Oswald being, you know, shot,” Trump told Fox News in May. “I mean, the whole thing is ridiculous. What is this? Right? Prior to his being shot. And nobody even brings it up.”

Trump appeared to be talking about a photograph published by the National Enquirer that showed Oswald and another man distributing pro-Castro leaflets in New Orleans in 1963. Cruz’s campaign denied that it was his father. No proof emerged supporting Trump’s claim.

Federal agencies have not been spared in Trump’s unsubstantiated attacks. The Fed, which operates separately from the executive branch, was “being totally controlled politically,” he said during remarks on the economy in New York last month.

“The system is rigged. General Petraeus got in trouble for far less. Very very unfair! As usual, bad judgment,” Trump tweeted in July, in response to the FBI recommending no charges against Clinton over her use of a private email server.

Lately, his rhetoric has become more personal — more about his movement, his supporters and himself.

“We’re going to watch Pennsylvania. Go down to certain areas and watch and study, make sure other people don’t come in and vote five times,” Trump said at a campaign stop in Altoona, Pa., in August, voicing concerns about voter fraud that he has repeated with urgency in recent weeks.

Studies have shown that documented instances of voter fraud are very rare and that efforts to tighten voter ID laws affect African Americans and younger voters more heavily than others.

Trump said Thursday that the world had reached “a moment of reckoning.” He told his backers that his campaign is “not about me; it’s about all of you, and it’s about our country.” He portrayed the powers he says have banded together to rally against him and his advocates as ruthless and cunning.

“They will attack you; they will slander you; they will seek to destroy your career and your family; they will seek to destroy everything about you, including your reputation,” Trump said. “They will lie, lie, lie, and then again they will do worse than that; they will do whatever is necessary.”

Jose A. DelReal and Jenna Johnson contributed to this report.