Latinos make up 25 percent of Arizona's eligible electorate and 17 percent of the state's registered voters. And in a race that polls show is tightening, even a small number of votes can decide who wins.
Both candidates, who still need to win their respective primary elections, are aware of the role Latino voters will play in the November election and are stepping up their outreach to this growing voting bloc.
McCain, who is seeking a sixth term in the Senate, has a Latino coalition called Unidos con McCain that he launched last October at Desert Sky Mall in West Phoenix. The coalition's co-chairs include Tucson Hispanic Chamber of Commerce president and CEO Lea Marquez-Peterson.
The coalition has been instrumental in setting up roundtable discussions between McCain and Latino leaders. So far, such events have been held in Tucson, Nogales, Sierra Vista, and Phoenix.
The senator's campaign, which includes a Hispanic outreach director, also has hosted a number of bilingual phone-banking and canvassing events. In addition, it has released bilingual digital ads that appear on social-media sites such as Facebook and Twitter.
"We really are targeting the Hispanic community, which we feel that the senator has a lot in common with," McCain spokeswoman Lorna Romero told New Times.
Kirkpatrick, meanwhile, has been doing her own Latino voter outreach.
She has been holding roundtable discussions with small groups of Latino leaders and doing interviews with Spanish-language media outlets. This weekend, she'll launch several field offices in areas with large Latino populations.
"Latino voters will decide who the next senator from Arizona will be," Kirkpatrick's campaign spokesman D.B. Mitchell told New Times. "We know that, and everybody else knows that. That's why we're working our butts off to make sure that Latinos know who Ann is, that they know her story, and that they know why she's going to be the best person to represent them in the Senate."
Kirkpatrick doesn't have the same level of name recognition among Latinos as McCain does. Many Latinos know who McCain is, in part, because he was a member of the "Gang of Eight" senators who crafted a comprehensive immigration-reform bill that included a path to citizenship for undocumented immigrants. The bill, introduced in 2013, passed in the Senate but stalled in the House of Representatives.
Kirkpatrick's campaign is working hard to improve the congresswoman's name recognition among Latinos. Its efforts include going door-to-door in Latino neighborhoods and hosting events where Latinos can meet Kirkpatrick.
The campaign also recently hired Raquel Terán, the former regional director of Mi Familia Vota who's well known among the Latino community, as its political director.
Kirkpatrick's campaign also aired a Spanish-language TV ad on Univision in the Phoenix and Tucson markets during the Copa America soccer games this past month. The spot reminds Latinos of the time McCain called for the completion of the "danged fence" during his re-election bid six years ago.
The "danged fence" ad didn't sit well with many Latinos, especially those who considered McCain an ally in the fight for immigration reform. But facing a difficult primary challenge from a Tea Party-backed conservative in 2010, McCain changed his tone on immigration and called for tougher border security.
"John McCain has become somebody who will walk away from these bills any time they stop being politically convenient," Mitchell said, referring to immigration-reform efforts.
Romero defended McCain, saying he has "made it very clear" that he's in favor of comprehensive immigration reform.
She added that even though McCain came out in support of Donald Trump — which also didn't sit well with Latinos — he thinks the presumptive Republican presidential nominee's plans to build a border wall and deport millions of undocumented immigrants "are not feasible."
"People try to spin his record however they want, but the reality is he has been pushing for immigration reform even when it was unpopular among his party," Romero said, adding that McCain worked with the late Democratic Sen. Ted Kennedy to try to pass a comprehensive immigration reform bill in 2007.
Kirkpatrick faces her own challenges. Many Latinos still remember that she missed the House vote on the DREAM Act in 2010. The bill — which McCain voted against even though he co-sponsored it in 2003 and 2004 — would have paved a path to citizenship for undocumented young immigrants who came to the U.S. as children.
In a radio interview earlier this month, Kirkpatrick said she missed the vote because she had a medical procedure scheduled that day. But she said she would have "rolled in" on a wheelchair or a gurney if her vote were needed to get the bill passed. The bill passed the House by a margin of 216-198 but failed in the Senate.
"I continue to be a very vocal advocate and supporter of the DREAM Act," Kirkpatrick added.
The primary election will be held August 30, and mail-in early voting begins August 3. McCain faces a challenge from three Republicans, while Kirkpatrick is running unchallenged. If McCain wins his primary, he'll face Kirkpatrick in the general election on November 8, for which early voting begins October 12.