PHOENIX - Democratic candidate for sheriff Paul Penzone leads six-term Maricopa County Sheriff Joe Arpaio, 48 percent to 44 percent, in a poll released Thursday by the Penzone campaign.
The poll might be the first time any candidate has topped Arpaio in a public opinion survey in recent memory. Penzone's lead in the poll, commissioned by his campaign, is within the margin of error of plus or minus 4.4 percent.
RELATED: Read the poll results
Penzone lost a three-person race to Arpaio in 2012 by six percentage points, but Arpaio barely garnered more than 50 percent of the vote, his poorest performance of any of his six campaigns.
The poll contains better news for Arpaio's chosen presidential candidate, presumptive Republican nominee Donald Trump. Trump leads presumptive Democratic nominee Hillary Clinton, 44 percent to 39 percent.
In 2012, Republican nominee Mitt Romney beat President Obama in Maricopa County by 10 points, 54 percent to 44 percent.
In a matchup of possible nominees in the U.S. Senate race, Republican Sen. John McCain led Democratic Congresswoman Ann Kirkpatrick, 50 percent to 35 percent.
Arpaio and Trump both posted the same results in the poll, but there were significant differences in each race. Fewer poll respondents were undecided in the the sheriff's race, while many more respondents in the presidential race said they planned to sit this one out.
"One of every 10 voters was telling us, 'We're not voting for either Clinton or Trump,'" said Drew Lieberman, senior vice president for research for Strategies 360, which runs the Penzone campaign.
Penzone has no opponents in the Democratic primary. Arpaio faces former Buckeye police chief Dan Saban, businesswoman Marsha Hill; and Wayne Baker in the Republican primary.
The survey of 503 likely voters in Maricopa County was done by live callers, and included Spanish-language voters and cell phone numbers.
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