FLAGSTAFF, Ariz. -- The man who hopes to wrest the Republican nomination away from four-term Arizona Sen. John McCain blasted the 2008 presidential candidate for his positions on immigration and border security at a Tea Party rally here on Sunday.
Former Congressman J.D. Hayworth, who has emerged as a formidable primary challenger to McCain, seized on amnesty for illegal immigrants and border control, which have become defining issues in the state's GOP Senate primary race.
"It is unconscionable that nearly a decade after 9/11 the backdoor of the United States remains open," Hayworth told hundreds of Tea Party members gathered at the Radisson Hotel in Flagstaff. "Our senior senator is looking at this entirely the wrong way."
Citing escalating drug violence along the U.S.-Mexico border and the murder of an Arizona rancher found shot to death on his Cochise County property on Saturday, Hayworth said, "It's not only a matter of national security, it's a matter of personal security."
But McCain still holds some clout among Tea Party activists, many of whom have not taken sides in the GOP primary, especially since he has the support of Sarah Palin, his 2008 running mate, who campaigned with him on Friday.
McCain campaigned alone on Saturday, and while he did not speak about border security, he addressed another kind of security equally important to Tea Partiers.
"The needs of Arizona today is the economy and jobs and jobs and jobs and jobs," said McCain, adding that he will fight for a balanced budget amendment to the Constitution.
McCain, who did not attend any Tea Party activities in Arizona over the weekend, also addressed his primary challenger on Saturday.
"I need your vote and I need it and I will be grateful for it. And I want it. And I work for you. I know this is a tough race. I intend to earn every single vote. And with your help, my friends, I will have the greatest honor of my life and that is the ability and the honor of being able to serve the most beautiful state in America, again, in the United States Senate," said McCain.
Hayworth on Sunday also frequently referred to his opponent. He mocked McCain and others' use of the phrase "comprehensive immigration reform," and he criticized McCain's co-sponsorship of legislation, including the 2005 McCain-Kennedy bill, which sought to pave the way for millions of illegal immigrants to earn citizenship.
"You and I in the real world know it better by a one-word description -- amnesty! And it's wrong!" he boomed.
Hayworth, a popular radio talk show host who is actively courting the backing of many Tea Party voters, said he wants to reintroduce The Enforcement First Act, a bill he sponsored during his tenure in the House to enforce existing immigration laws.
In an interview with FoxNews.com, Hayworth said he's also calling for increased manpower to patrol the border, including the National Guard and standing military.
The influx of illegal immigrants across the U.S.-Mexico border has become a growing point of contention between Arizona residents and state and federal lawmakers -- and an issue the Tea Party movement says could well determine the outcome of the Aug. 24 primary.
A July 2009 Rasmussen poll showed that 51 percent of Arizona voters said it was more important for Congress to pass immigration legislation than a health care reform bill. And 65 percent said enforcing the border was paramount to legalizing the status of illegal immigrants already in the U.S.
That same polling firm found in a poll taken March 16 that McCain trumps Hayworth 48-41 percent among 541 Arizona voters surveyed, though McCain has fallen below the 50 percent mark and Hayworth has won the backing of former Minuteman leader Chris Simcox, who also briefly flirted with a McCain challenge.
At Sunday's Tea Parties in Phoenix and Flagstaff, dozens of local organizers expressed anger over border security, but few offered viable solutions -- underscoring the complexities and hurdles of securing the 2,000-mile stretch of land along the U.S. southern border.
"There's not a single Tea Party member who doesn't feel immigration is our most important issue in Arizona right now," said Carol MacDonald, a member of the West Side Avondale Party, one of several Tea Party factions within the state.
"They don't pay taxes because they're illegal and they're draining the money we've all worked and saved for our retirement," she said. "And the people who are here legally from other countries are just offended as we are."
Cristina Corbin is a Fox News reporter based in New York. Follow her on Twitter @CristinaCorbin.