Former President Donald J. Trump posted a video on Monday afternoon that features images of hypothetical newspaper articles celebrating a 2024 victory for him and referring to “the creation of a unified Reich” under the headline “What’s next for America?”

The 30-second video, which Mr. Trump posted on his social media site, Truth Social, features several articles styled like newspapers from the early 1900s — and apparently recycling text from reports on World War I, including references to “German industrial strength” and “peace through strength.” One article in the video asserts that Mr. Trump would deport 15 million migrants in a second term, while text onscreen lists the start and end days of World War I.

Another headline in the video suggests that Mr. Trump in a second term would reject “globalists,” using a term that has been widely adopted on the far right and that scholars say can be used as a signal of antisemitism.

The Trump campaign said in a statement that the video had been posted by a staff member while Mr. Trump was in his criminal trial in Manhattan. The video was still up on his account late Monday night, and his campaign did not respond to a question about why it had not been taken down.

“This was not a campaign video, it was created by a random account online and reposted by a staffer who clearly did not see the word, while the President was in court,” Karoline Leavitt, a campaign spokeswoman, said in a statement. “The real extremist is Joe Biden.”

Mr. Trump has repeatedly denounced Jews who vote for Democrats, accusing them of hating their religion and Israel. In one video this month, he said that “if Jewish people are going to vote for Joe Biden, they have to have their head examined.”

Mr. Trump, whose advisers have been crafting plans for a second term that would be more radical than his first, has also drawn criticism during this campaign for echoing the language of past authoritarian leaders, dehumanizing his political opponents as “vermin” and promising that he would not be a dictator “except for Day 1.”

In November 2022, Mr. Trump had dinner with Nick Fuentes, an outspoken antisemite who is one of the country’s most prominent white supremacists. He has also tried to downplay the violent white supremacist rally in Charlottesville, Va., in 2017, describing the episode as “a big hoax.” One woman was killed and nearly 40 people were injured when an avowed neo-Nazi plowed his car into a crowd.

The term “Reich” is often associated with Germany’s Nazi government under Adolf Hitler, who established a “Third Reich” that succeeded its first two counterparts, the medieval Holy Roman Empire and the German Empire of 1871-1918, which lost World War I to the Allied powers.

The sentence referring to “the creation of a unified Reich” is used three times in the video. It reads, in full, “German industrial strength significantly increased after 1871, driven by the creation of a unified Reich.” In the beginning of the video, as an announcer asks, “What’s next for America,” the text is partly visible, including the words “the creation of a unified Reich.”

The German Empire that fought in World War I was founded when many different German-speaking states and regions were unified — some by force — into a single, powerful nation in 1871. That empire was dismantled at the end of World War I, and Hitler stoked resentment against the loss of former German territories, and against the Jewish people, as he rose to power in the lead-up to World War II.

President Biden’s campaign accused Mr. Trump of echoing Nazi Germany by posting the ad, saying in a statement on social media that the video was “foreshadowing a second Trump term.”