In those situations, having members of both parties present reduces the risk that observers might think poll workers are trying to benefit one side or another, said Barry Burden, director of the Elections Research Center at the University of Wisconsin-Madison.
“It should build trust in the system, because it means that each polling place, if it were staffed by at least one Republican and one Democratic poll worker, has a monitor from each party essentially keeping eyes on what’s happening,” Burden said.