A poll conducted by Phoenix-based OH Predictive Insights (OHPI) has McSally ahead by 8 points over her toughest primary opponent, former state Sen. Kelli Ward (R), 35 to 27 percent. Former Maricopa County Sheriff Joe Arpaio is far behind in third, with 15 percent. Twenty-three percent of voters remain undecided going into Arizona’s primary on Aug. 28.

McSally’s lead over Ward dipped by 6 points since OHPI’s poll from mid-June. In the June poll, the congresswoman held a comfortable 14-point lead over Ward, who has kept up her heavy attacks on McSally related to President Trump and immigration.

“The Arizona Senate contest is tightening and expect the attacks to ramp up as we head closer to election day,” said Mike Noble, managing partner and chief pollster at OH Predictive Insights.