Gov. Tony Evers of Wisconsin activated about 500 members of his state’s National Guard ahead of the verdict in Kyle Rittenhouse’s homicide trial in Kenosha. Officials said the troops would be placed on standby outside the city but would be ready to help if requested by local law enforcement.

“I urge folks who are otherwise not from the area to please respect the community by reconsidering any plans to travel there and encourage those who might choose to assemble and exercise their First Amendment rights to do so safely and peacefully,” Mr. Evers said in a statement.

Last year, after a white Kenosha police officer shot Jacob Blake, a Black man, several nights of demonstrations in the city turned violent and destructive. Mr. Evers sent hundreds of guardsmen to the city in response.

It was amid that chaos that Mr. Rittenhouse, a teenager from Illinois, came to downtown Kenosha with a high-powered rifle and a first aid kit, claiming he intended to protect property and provide medical care.

But as the night turned more tense, Mr. Rittenhouse shot three people, killing two of them. Prosecutors charged him with homicide and accused him of opening fire with no legal justification. Mr. Rittenhouse, whose cause has been championed by many conservatives and gun rights activists, has claimed self-defense.

In the months that followed, Kenosha remained peaceful when local prosecutors declined to charge the officer who shot Mr. Blake, and when federal prosecutors said they would not pursue charges against the officer.

Mr. Rittenhouse’s trial, which has played out this month at a courthouse near the shooting scene, has been watched closely, but without significant disruption or large protests in the city. Still, some have been uneasy about potential reaction to the verdict.

“We’ve been in contact with the governor’s office and there are plenty of resources available if needed,” Sheriff David Beth of Kenosha County said. “We’re prepared for any situation as this trial comes to a close.”