Arizona Sen. John McCain says primary voters sent a clear message this week that they're angry and frustrated.
The Republican is seeking his fifth term in the U.S. Senate and on Friday downplayed comparisons of his tough re-election battle to the campaigns of other longtime senators who recently lost their primaries.
He says the senators who lost were all defenders of earmarks — special federal funding set aside for specific, home-state projects.
McCain has long opposed earmarks, calling the process "pork-barrel" spending that leads to corruption.
McCain spoke after turning in petition signatures to qualify for the ballot.
Former conservative talk-radio host J.D. Hayworth, who also served in the U.S. House, is challenging McCain in the Aug. 24 primary.
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