Phoenix ? Defeated just two years ago as the Republican presidential candidate and with his bonafides as a true conservative again being challenged, John McCain finds himself in a struggle to get even his party’s nomination for another term in the Senate.

Many conservatives and Tea Party activists are lining up behind Republican challenger and former talk radio host J.D. Hayworth, reflecting a rising tide of voter frustration with incumbent politicians. Only 40 percent of Arizonans have a favorable view of McCain’s job performance.

Faced with his toughest re-election battle ever, McCain has moved to the right on several hot-button issues, like gays in the military and climate change, and has built a campaign war chest of more than $5 million. Former running mate Sarah Palin and newly elected Republican Sen. Scott Brown, both popular with conservatives, are pitching in.