With less than two weeks until Election Day, law enforcement officials are confronting a rising wave of threats to election workers and political activists in a presidential contest hurtling towards a bitterly contentious coda and a potentially unsettled aftermath.

On Monday, the justice department unsealed a complaint against a man in Philadelphia who had vowed to skin alive and kill a party official recruiting volunteer poll watchers. On Tuesday, the police in Tempe, Arizona, arrested a man in connection with shootings at a Democratic campaign office, which resulted in no injuries.

On Wednesday, prosecutors charged a 61-year-old man from Tampa, Florida, with threatening an election official — on top of pending charges over menacing messages sent in the past five years. And on Thursday, police officers in Phoenix arrested a person in connection with a mailbox fire, damaging some 20 ballots in a Democratic stronghold.

Law enforcement’s task this year goes far beyond the relatively straightforward job of providing physical security — to the essential mission of safeguarding the election from individuals and groups who want to instill fear and uncertainty, even if they never resort to violence.

Political battlegrounds are taking on the sobering characteristics of actual ones. Drones, barriers and snipers are expected to be deployed at some offices and polling sites. Bulletproof glass and armed security patrols are becoming commonplace everywhere.

“The fact that election workers need to be worried about their security is incomprehensible and unacceptable,” Christopher A. Wray, the director of the FBI, said in a statement on Wednesday.