Hillary Clinton channeled a little bit of Donald Trump in San Diego on Thursday afternoon, delivering a blistering attack on her likely Republican opponent's qualifications to run the country.

"Making Donald Trump our commander in chief would be a historic mistake," Clinton told a cheering, and at times laughing, audience.

Clinton repeatedly invoked the threat of nuclear war, warning that Trump's inexperience and proclivity for feuds would make a dangerous mix. "This is not someone who should ever have the nuclear codes. Because it's not hard to imagine Donald Trump leading us into a war just because somebody got under his very thin skin," Clinton said.

"He is not just unprepared," she argued. "He is temperamentally unfit to hold an office that requires knowledge, stability and immense responsibility."

Clinton criticized Trump for questioning the value of the European NATO alliance, for suggesting that countries like Japan and South Korea should develop nuclear weapons, and his calls to temporarily ban all Muslims from entering the United States.

"His proposal to ban 1 1/2 billion Muslims from even coming to our country doesn't just violate the religious freedom our country was founded on, it's a huge propaganda victory for ISIS," she said.

"We all know the tools Donald Trump brings to the table," said Clinton. "Bragging, mocking, composing nasty tweets. I'm willing to bet he's writing a few right now."

Indeed, he was.

Clinton's speech previews the likely line of attack that her campaign will make against Trump between now and November. (And November was clearly the focus. Despite polls showing an increasingly tight race in California between her and Bernie Sanders, Clinton didn't mention the Vermont senator once.)

It came a bit more than a month after Trump delivered a major foreign policy address of his own, where he blamed the Obama administration's approach to the world as "reckless, rudderless and aimless."

While decisions Clinton helped shape as secretary of state, such as the intervention in Libya, have left her open to criticism, her argument at times boiled down to the fact that she's experienced in the field. Clinton walked through a brief overview of her tenure as secretary of state, senator and first lady, before lampooning what she framed as Trump's naiveté.

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