LAKE HAVASU CITY, Ariz. – A serious re-election fight wasn’t what Republican John McCain expected when he returned to the Senate after losing the presidency.

But the four-term senator is battling for his political life in a race that embodies the volatility of an unpredictable election year. He’s facing former Rep. J.D. Hayworth, a fellow Republican pushing him farther to the right as GOP voters demand conservative purity in their candidates and punish those with ties to the Washington establishment.

Two longtime Senate incumbents have fallen — Bob Bennett, R-Utah, and Arlen Specter, D-Pa. A third — Blanche Lincoln, D-Ark. — could see her hopes dashed this Tuesday in a runoff amid voter inclination to reward political neophytes who adhere to party principles over experience.

McCain’s popularity fell in Arizona as he spent years campaigning outside of it, twice for the White House. Hayworth, a radio talk show host who had been in Congress for a dozen years but lost to a Democrat in 2006, saw a chance for a political comeback.

The behemoth in the race, McCain has a decades-old political organization, millions in the bank and six campaign offices. He’s counting on his deep ties to Arizona and legions of longtime backers to carry him through. In contrast, Hayworth has never run statewide, is struggling to raise money and has just two offices. But he’s being fueled by disaffected McCain backers and voters hungry for new leadership.

“He’s been there too long. And he hasn’t done anything for Arizona,” Ally Miller says of McCain, 73. “It’s time for someone new.”

Among Hayworth supporters, there’s a feeling that McCain hasn’t been a loyal Republican, he’s ignored Arizona and his time has passed. Many have voted for him for years — because, they say, there wasn’t another option. With the 51-year-old Hayworth, people fed up with the status quo — and unwilling to automatically give McCain a new six-year term — have somewhere to turn.

“Hayworth is a true conservative patriot,” said a supporter, John Kessler. “McCain has become a big government, tax-and-spend liberal.”