Arizona Sen. John McCain is facing a serious primary challenger: Republican J.D. Hayworth, a former congressman and radio talk-show host who calls himself the “consistent conservative.”

When he formally kicked off his campaign in February, the bombastic Hayworth cast himself as the champion of the insurgent Tea Party revolution, calling the campaign “a classic political confrontation: John McCain and the Washington establishment on one side, and we the people on the other.”

Hayworth has dinged McCain on everything from being soft on border security to opposing drilling in the Arctic. He’s even complained that “just like the liberals, John opposes waterboarding captured terrorists like the Christmas bomber.”

Hayworth’s attacks have forced McCain to move to the right on nearly every issue in an effort to reinvents himself; earlier this year, he went so far as to declare: “I never considered myself a maverick.”

McCain has hit back by ridiculing Hayworth as a birther and hammering him as a pork-barrel spender. Most recently, his campaign released an ad mocking Hayworth for

incorrectly telling a crowd that the United States never declared war on Germany during World War II.

Most polls have shown McCain holding a double-digit lead over Hayworth, although they’ve also showed that Arizona’s senior senator is the choice of only about half of the Republicans surveyed.

Republican Jim Deakin, a little-known political newcomer, is also in the GOP race.

The lively primary has a number of Democrats lining up to take on the GOP primary winner. The best-funded is Rodney Glassman, who gave up his seat on the Tucson City Council earlier this year to run. Glassman has lined up a number of high-profile endorsements, including support from Congressman Raúl Grijalva, labor activist Dolores Huerta and the Arizona AFL-CIO, and he’s raised a quarter-million dollars—which he’s matched with a quarter-million from his own wallet, according to the Glassman campaign.

“For over 28 years, John McCain has been ignoring Arizona,” Glassman says. “We need a representative in the U.S. Senate who’s committed to working for Arizona’s future.”

Three latecomers have spoiled Glassman’s hope of avoiding a primary fight. Investigative reporter John Dougherty, who worked more than a decade for the Phoenix New Times, promises to run an aggressive, albeit low-budget campaign that challenges the entire political status quo.

“Part of our theme is accountability now,” Dougherty says. “Nobody is holding these guys accountable, and it’s just going to turn into platitudes and B.S. without really talking about the situation that we’re facing. We’ve got the police state; we’ve got a militarized border; we’ve got a war on drugs; we’ve got all this stuff that no one is bringing into the debate. But we will.”

Randy Parraz, a California native who attended the University of California at Berkeley’s law school and Harvard’s Kennedy School of Government, has been working as a labor organizer with immigrant workers in Maricopa County for about five years.

Parraz says he was approached by a variety of activists in recent months who encouraged him to run for the U.S. Senate.

“They want someone who is really strong on the issues and can push a more progressive voice,” Parraz says. “Someone who has a history of being able to fight for social change and make things happen.”

Former state lawmaker Cathy Eden rounds out the Democratic field. Eden, who served in the Arizona House of Representatives from 1990 to 1994, managed several state departments, including the Department of Health Services under Govs. Jane Dee Hull and Janet Napolitano.

Green Party candidate Jerry Joslyn and Libertarian David Nolan will appear on the general election ballot. Nolan, who ran for Congress in District 8 in 2006, helped found the Libertarian Party in 1971.

Republicans

John McCain's Web site

J.D. Hayworth's Web site

Democrats

Rodney Glassman's Web site

John Dougherty's Web site

Randy Parraz's Web site

Cathy Eden's Web site

Libertarian

David Nolan's Web site

Green Party

Jerry Joslyn's Web site