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. Conservatives, independents 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.