NEW YORK — Hillary Clinton may have found her message.

Wrapped in the guise of a foreign policy speech, Clinton delivered a political thrashing of Donald Trump on Thursday that was unquestionably a standout moment for a candidate who has often struggled to focus her White House campaign.

Clinton’s sharply targeted remarks served notice on the presumptive Republican nominee that she’s prepared for a bruising general election fight, one that’s centered squarely on his competency to serve as commander in chief.

“He is not just unprepared — he is temperamentally unfit to hold an office that requires knowledge, stability and immense responsibility,” Clinton said.

She cast Trump as dangerously thin-skinned, someone who might plunge the nation into war over a perceived slight. She repeatedly referred to her White House rival by his first name only — a knowing dig at a billionaire businessman whose closest advisers reverentially call him “Mr. Trump.”