Voters cannot advocate or display support for specific candidates and ballot measures within a hundred feet of vote centers or drop boxes.
"Prohibited actions include vocal advocacy, wearing materials with candidates' names, likeness, or logo. The distribution of buttons, stickers, pens, or other materials containing electioneering information," Fresno County Clerk and Registrar of Voters James Kus said.
Kus says his election workers are prepared to enforce the law. They will ask voters to remove or cover signs, shirts, and flags with candidate names and logos.
However, there are exceptions.
"Material that is not on the current ballot does not fall under this prohibition," Kus said. "Slogans do not fall under this prohibition."
Officials say the law prevents voter intimidation, something Fresno County District Attorney Lisa Smittcamp says her office takes seriously and could prosecute.
"It's not your First Amendment right to threaten people," Smittcamp said. "Additionally, intimidation of voters or interference with election activities are crimes."
The possibility of physical threats or intimidation comes amid heightened political rhetoric that officials worry could boil over.
ABC News obtained documents the Department of Homeland Security's Intelligence Office sent law enforcement. Government officials say they are concerned the current environment could lead to election-related violence.
"We are not aware of any credible threats here in Fresno County related to Tuesday's November 5th election," Fresno County Sheriff John Zanoni said.
Zanoni says his deputies would respond to potential Election Day threats at vote centers and drop boxes on county property.
Federal officials are also on standby. The U.S. Attorney's Office has named a District Election Officer to oversee federal complaints about potential fraud and voting rights abuses.
"If an incident that has federal elements comes to the police department or sheriff's department, we would refer that over to the U.S. Attorney's Office," Smittcamp said.
The District Attorney's Office has already received one referral of potential electioneering in Fresno. However, officials say most voters are respectful and cooperate with election workers.