There's a brief but interesting article up on the American Prospect site by music historian J. Lester Feder that plays off the Dixie Chicks "controversy" to remind people that country music's famous political conservatism was yet another legacy of Richard M. Nixon's Southern Strategy.
Feder's right that country music got politicized in the Nixon Years, and I can add a few examples to his account, from personal memory.
He rightly tags Merle Haggard's "Okie From Muscogee" as the apotheosis of country conservatism, and reports ol' Merle's claim that the song was a parody. He doesn't mention Merle's follow-up superpatriot hit, "The Fightin' Side of Me", that was clearly beyond parody:
I read about some squirrely guy who claims that he just don't believe in fighting
And I wonder just how long the rest of us can count on being free
They love our milk and honey but they preach about some other way of living
But when you're running down my country, hoss
You're walkin' on the fightin' side of me.
This tune anchored a live album, recorded in Philadelphia, that was a red-white-and-blue extravaganza. I remember it vividly. My parents, huge Haggard fans (they actually got to hang out with him a bit at an Atlanta country music venue called the Playroom, in those innocent, pre-arena days of the genre), naturally had a copy, and made sure I heard the cut that included his spot-on impressions of other country stars, most notably fellow Bakersfield legend and country-rock pioneer Buck Owens (whose ex-wife Bonnie was Merle's then-wife and backup singer).
Haggard did, a couple of years earlier, turn down a request from George Wallace to endorse his 1968 presidential candidacy. But other country stars--if I remember correctly, they included both Tammy Wynette and Loretta Lynn--did sing for George. And one of my favorite memories from the 1968 campaign was an ad featuring Grand Ol' Opry fixture Roy Acuff, who did a soulful musical intro about the nation's many problems, and then the camera pulled back to show Roy standing next to a gigantic, hideous photo of Richard Nixon (Acuff himself ran for Governor of Tennessee as a Republican back in 1948, and in 1970, campaigned for fellow country singer Tex Ritter in 1970, running for the same office with the same futile result).
Perhaps the best example of the abrupt transition from populism to conservatism that Leder talks about was Whisperin' Bill Anderson, a Georgia country crooner whose band, the Po' Boys, was rooted in the Depression populist tradition. But in the early 70s, he did a song, "Where Have All Our Heroes Gone?" that arguably captured the rightward, nostalgic trend in country music more presicely than Haggard's pugilistic odes (though Loretta Lynn's "God Bless American Again," co-written with Conway Twitty, which she typically delivered against a backdrop that featured a spotlighted Old Glory, did so as well in a less explicitly political vein).
The omission in Leder's piece that surprised me the most was the obvious antecedent to the Dixie Chicks' liberal heresy: Earl Scruggs. An alumnus of Bill Monroe's band, co-founder of the vastly popular Flatt and Scruggs duo, and basically, the inventor of bluegrass banjo pickin', Scruggs scandalized much of his following by performing at the big 1969 anti-Vietnam War rally in Washington.
And Earl's still around, probably chuckling a bit at the Chicks' successful notoriety and multiple Grammies. Scruggs picked up his first Grammy the same year as his anti-war appearance, for Foggy Mountain Breakdown, and won a second Grammy for a re-recording of the same piece, in 2002. --