PHOENIX — Likely voters in Arizona’s upcoming Republican primary have been lining up behind front-runner Rep. Martha McSally in greater numbers recently, according to a poll.

McSally has pulled out to a 20-point lead in the race for U.S. Senate over her closest rival, Dr. Kelli Ward, in an OH Predictive Insights/ABC15 phone survey conducted Tuesday and Wednesday.

The Tucson politician leads Ward, a former state senator, 47.4 percent to 27 percent. A poll earlier this month had McSally up, 35 percent to 27 percent. The third candidate, former Maricopa County Sheriff Joe Arpaio has fallen from 15 percent to 13.3 percent.

“This race is Martha’s McSally’s to lose,” OH Predictive chief pollster Mike Noble told KTAR News 92.3 FM.

The landline survey began the day after President Donald Trump mentioned McSally in remarks made after he signed the John S. McCain National Defense Authorization Act in Fort Drum, New York. McSally was in attendance.

Undecideds have also dropped off, from 23 percent two weeks ago to just over 12 percent.

“Those (previous) undecideds gravitated over to Martha McSally,” Noble said.

He added that over a third of the 578 likely voters surveyed said they had already returned ballots and another third planned on sending in their ballots. Less than 30 percent said they would vote at the polls.

Arizona’s primary will be held Aug. 28; the general election follows Nov. 6.

Respondents were broken into two age groups — 54 or younger and 55 and older. The older group was the largest, at 78 percent. Men made up 52 percent of the group. Nearly 11 percent said they were independent.

The margin of error for the poll was plus or minus 4 percent.

KTAR News 92.3 FM’s Ashley Flood contributed to this report.

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