The closing arguments have been delivered by former President Donald J. Trump in New York’s Madison Square Garden and by Vice President Kamala Harris on the Ellipse in Washington, with the White House as her backdrop.

But in the final days of the tightly drawn presidential campaign, the last messages to voters in the seven swing states that will decide the election continue to flood televisions, computers and smartphones.

From Ms. Harris and her supporters, those messages cover a mix of kitchen-table issues on the economy and taxes, the fate of legal abortion and the dangers posed by a return of Mr. Trump to the White House.

For Mr. Trump and his allies, one message dominates: Defeating Ms. Harris is a matter of life and death. Your death, to be specific.

“How will your family survive another four years if you may not be able to survive the night?” asks one ad from the super PAC Right for America. It received a $7 million run in October.

An analysis by The New York Times and the tracking firm AdImpact of the largest advertising purchases in the final weeks of the campaign found clear patterns. The five largest purchases from four corners — the Trump campaign, the Harris campaign and the biggest political action committees supporting each of them — show distinct tactics.