Hillary Clinton may have cracked the code on how to land a real blow to Donald Trump.

He has proven a maddeningly elusive target for Republicans and Democrats alike. But on Thursday in San Diego, Clinton delivered what was easily her toughest speech yet on the presumptive Republican nominee, deploying a potent combination of her well-known policy wonkishness with a surprising dose of ridicule.

“It’s clear he doesn’t have a clue what he’s talking about,” she urged, and added, “If Donald gets his way, they’ll be celebrating in the Kremlin.” Close video Clinton targets Trump in foreign policy speech Democratic presidential candidate Hillary Clinton makes remarks on why Republican presidential candidate Donald Trump is unfit to be President of the United States. Democratic presidential candidate Hillary Clinton makes remarks on why Republican presidential candidate Donald Trump is unfit to be President of the United States. share tweet email Embed

It’s too early to know for sure whether it will work, and if she becomes the Democratic nominee as expected she’ll need to repeat the message a few thousand times before November for it to stick. But Clinton’s performance, the latest and most effective in a series of putative “opening salvos” of the general election, was immediately hailed by Democrats as a welcomed change for a candidate who often struggles to transcend policy minutiae.

“It wasn’t just an incredibly well written speech, it was arguably Clinton’s most compelling public moment of the entire campaign so far,” said Simon Rosenberg, founder and president of NDN, a Democratic think tank.

Foreign policy is typically discussed in somber tones befitting the seriousness of war and peace. While some may lament Clinton’s delivery – at times strident, sarcastic and even humorous – the candidate and her aides seem to have concluded the attitude was the missing factor they need to take on a former reality TV star. But unlike Marco Rubio’s brief attempt to give Trump a taste of his own medicine during the GOP primary, Clinton’s mockery Thursday stayed within the bounds of policy issues.

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Clinton heaped zinger after zinger on her presumptive rival as the audience laughed and whooped like they were watching a comedic roast. Trump is often credited for voicing what many people are thinking but rarely willing to say out loud, and Clinton seemed to take the same blunt approach to him.

“I’ll leave it to the psychiatrists to explain [Trump’s] affection for tyrants,” Clinton said.

“This isn’t reality television – this is actual reality,” she quipped.

“There’s no risk of people losing their lives if you blow up a golf course deal, but it doesn’t work like that in world affairs,” Clinton quipped again.

She called Trump’s foreign policy ideas “a series of bizarre rants, personal feuds and outright lies,” and warned, “It’s not hard to imagine Donald Trump leading us into a war just because somebody got under his very thin skin.”

Indeed, getting under Trump’s skin seemed to be Clinton’s main objective. While she didn’t use nicknames for the Republican, who has a moniker for every opponent but prefers to be called “Mr. Trump,” Clinton repeatedly belittled him by referring to him as “Donald.”

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Clinton aides heavily promoted the speech, and the billing helped Clinton break through and seize a moment of attention in a news environment dominated by Trump. The sharp one-liners that peppered her remarks will make it more likely for her message to reach voters who didn’t tune in live on a Thursday afternoon to watch, since the soundbites will get shared on social media and played on news broadcasts for days to come.

As she kept her fire trained on Trump throughout the entire speech, Clinton was speaking to several different audiences at once.

“I think that speech was basically appealing to independents and Republican who are turned off by Trump,” said Larry Korb, a former Pentagon official under Ronald Reagan who now works for the liberal Center for American Progress.

Close video Clinton: Trump ‘Temperamentally Unfit’ to be President Hillary Clinton launches an all-out assault on Donald Trump’s foreign policy, slamming the presumptive GOP nominee as a dangerous know-nothing temperamental liar who will lead us into nuclear war. Ian Bremmer of the Eurasia Group weighs in. Hillary Clinton launches an all-out assault on Donald Trump’s foreign policy, slamming the presumptive GOP nominee as a dangerous know-nothing temperamental liar who will lead us into nuclear war. Ian Bremmer of the Eurasia Group weighs in. share tweet email Embed

Other parts of her message seemed tailored for swing voters in the handful of states that will decide the election, like Ohio and Florida. “We cannot put the safety of our children and grandchildren in Donald Trump’s hands. We cannot let him roll the dice with America,” Clinton said, one of several times she invoked voters’ children.

Finally, much of her message – delivered in California just days before voters head to the polls in a tight Democratic primary there – seemed intended for the wide swath of Democrats who are still not sold on Clinton.

The Democratic front-runner was trying to say she is uniquely qualified to go after Trump, thanks to her experience as secretary of state, said Heather Hurlburt, a veteran Democratic foreign policy hand and speechwriter.

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“If you find Trump obnoxious, bigoted, scary and you watch some of the red meat clips in there, that’s going to be highly motivating to get out to the polls next week,” Hurlburt said. “All of which is interestingly an implicit critique of [Bernie] Sanders.”

Indeed, the benefits of taking on Trump regarding international affairs are obvious for Clinton.

But there is also a risk that, by appealing to people like Bill Kristol and defending a muscular global role for America on the world stage, Clinton feeds Sanders supporters’ suspicions about her foreign policy.

Clinton began her speech by saying the election is “a choice between a fearful America that’s less secure and less engaged with the world. And a strong, confident America that leads to keep our country safe and our economy growing.”

Sanders supporters, like Trump’s, are highly skeptical of America’s internationalist engagement.

According to Pew analysis of survey data, Sanders supporters are less likely than other Democrats to say the U.S. should help other countries deal with their problems, and more likely to say the U.S. involvement abroad actually makes things worse as better. Likewise, according to Pew, Trump supporters are more likely than other Republicans to say the U.S. does too much in solving the world’s problems.

That might help explain why Clinton mostly focused on attacking Trump’s temperament and character, rather than his overall foreign policy philosophy.

“As far as I could see, I don’t think she alienated any of the people who might be supporting Bernie on foreign policy,” said Korb, whom the Sanders campaign has listed as a foreign policy advisor.