After running his campaign on a shoestring for months, thanks to the news media’s obsessive attention, Donald J. Trump has released his first campaign commercial, promising to stop illegal immigration and defeat the Islamic State, also known as ISIS or ISIL.

On Screen

The entire ad is shrouded in darkness of one kind or another: naval and aerial bombardments, surveillance video of blurry figures swarming what looks like an unguarded border, even the shadowed faces of Hillary Clinton and President Obama — which not-so-subtly give way to shots of the husband-and-wife killers in San Bernardino, Calif., with a body bag being wheeled behind them. Mr. Trump almost shouts his “I approve this message” statement at the start; a deep-voiced narrator then gets down to the business of button-pushing, saying, as sirens whine: “The politicians can pretend it’s something else, but Donald Trump calls it radical Islamic terrorism.”

Mr. Trump’s call to bar Muslims from entering the United States is trumpeted, as a photograph of a crowded airport security line dissolves into one insinuating the risk if Muslims are not barred: masked, armed Syrian jihadists in your neighborhood. Same for the promise of a border wall “that Mexico will pay for”: Without it, the ad implies, you are not safe.

The Message

Fear, centered on immigration, the explosive issue underpinning Mr. Trump’s candidacy. Even his promise to “quickly cut the head off ISIS — and take their oil” is sandwiched between two promises about immigration.