WASHINGTON — Hillary Clinton opened her general election campaign against Donald Trump on Wednesday by accusing him of behaving like a “demagogue,” likening his attacks on judges, the media, his opponents and their families to dark moments in world history.

“It’s classic behavior by a demagogue,” she told The Associated Press. “We’ve seen it many, many places and times in the world, and that’s why I think it’s so dangerous.”

The presumptive Democratic nominee, who declared victory in her race against Vermont Sen. Bernie Sanders on Tuesday, a day after reaching the number of delegates needed to claim the nomination, seemed to wonder whether Trump’s candidacy was little more than an elaborate political stunt.

“I don’t know if this is just, you know, political gamesmanship that he thinks plays to the lowest common denominator, but whatever the reason for it is, it’s wrong and it should not be tolerated by anybody,” she said.

But even as she questioned the sincerity of the real estate mogul’s rhetoric, Clinton said voters need to take his words seriously and called them evidence that he is untrustworthy, unqualified and unprepared for the rigors of the White House.

While the two candidates have never been personally close, their political and financial circles have occasionally overlapped over the years – especially during Clinton’s time as a senator from New York, Trump’s home state. Clinton and her husband, former President Bill Clinton, attended Trump’s third wedding in 2005, and she said later that she thought Trump was “always entertaining.”

But Clinton expressed surprise at what she described as the billionaire’s descent into “conspiracy theories” in recent years.

“He always had opinions which he freely expressed,” she said.

“I never really ever had any information about him engaging in bigotry and prejudice until he took up the cause of the birthers against President Obama, which is really so bizarre,” she added, with an incredulous laugh.

Clinton and Democrats supporting her are attempting to cast Trump as a ruthless con artist who is tricking voters in the same way he duped prospective students into enrolling into his now-defunct Trump University, a business that offered real estate seminars.

It’s an argument Clinton and her aides believe will appeal not only to Democrats, but independent voters and even some Republicans.

While stopping short of calling Trump a racist for his comments about the federal judge overseeing a class-action lawsuit against Trump University, Clinton said her rival has a “very unfortunate and divisive tendency to attack all kind of Americans.”

While Clinton seeks to paint Trump as a dangerous huckster, he has spent the past several weeks since claiming the Republican nomination working to define her candidacy. Trump refers to her as “Crooked Hillary” and often says she belongs behind bars for her use of a private email account and server during her time as secretary of state.

“The Clintons have turned the politics of personal enrichment into an art form for themselves,” Trump said Tuesday as he won the final five Republican primaries. “They’ve made hundreds of millions of dollars selling access, selling favors, selling government contracts, and I mean hundreds of millions of dollars.”

Trump promised to deliver a speech next week focusing on “the Clintons.” He’s also tried to re-ignite past scandals that dogged Bill Clinton’s administration, including his impeachment trial and the Whitewater land deal in his native Arkansas.