Carrie Underwood received nominations for Female Vocalist and Album of the Year from the Country Music Association Wednesday morning. However, Carrie, the reigning Entertainer of the Year for the Academy of Country Music, was left off the CMA's list for the equivalent category -- as was last year's winner, Taylor Swift. Instead, the CMA's Entertainer of the Year contenders are Lady Antebellum, Brad Paisley, Keith Urban, the Zac Brown Band and Miranda Lambert, who set a CMA record with nine nominations, the most for any female singer in the organization's history.

The CMA Awards will be broadcast from Nashville's Bridgestone Arena on Nov. 10. For a complete nominees' list, click here.

Thursday, Entertainment Weekly's Whitney Pastorek posted a piece wondering why Carrie Underwood got overlooked for theCountry Music Association's Entertainer of the Year award. Her basic theories: 1) Maybe she's too pop; 2) maybe voters still hold American Idol against her; and 3) sexism. Solo female singers have gotten no more than one slot in the Entertainer of the Year category since 1979, and that spot went to formerNashville Star second runner-up Miranda Lambert this year.

As a former member of the CMA's board of directors, I'll throw one other possible explanation into the mix, though, admittedly, it doesn't make for a very satisfying reason: Sometimes CMA voters just get in a mood.

When that happens, it's the musical equivalent of a "throw the bums out" political climate. The electorate -- which, in this case, consists of members of the music industry, from artists to radio to record companies to assorted other support positions -- gets fed up with the status quo and decides to recognize a new crop of acts that the industry wants to have represent it, not what the fans actually like best and support most.

Right now, Miranda Lambert is the best example of that act. And once voters started casting their votes for Lambert, they went anti-establishment every chance they got, putting Lambert in every available slot then voting for fiancee Blake Shelton (to the point that his Hillbilly Bone single with Trace Adkins, an entertaining novelty, will compete with two Lambert cuts for Single of the Year). And then they went for the Zac Brown Band, Dierks Bentley's bluegrass project and Lady Antebellum (who aren't exactly anti-establishment, but they do kind of represent a new paradigm for country groups and they are good buds with Lambert).

CMA voters usually do this sort of thing in one category each year, usually in Musical Event or Music Video. But it happened in a big way in 1995, when Alison Krauss won Female Vocalist of the Year, when Reba McEntire, Pam Tillis and Mary Chapin Carpenter had all had bigger hits and Shania Twain wasn't even nominated.

It happened again with Dixie Chicks in 1999 and 2000: In 1999, the Chicks got an Entertainer nomination despite not having headlined a tour, and you could tell voters were looking for an excuse to give them the top award, which they did in 2000.

Voters sent the message in a big way in 2001, when the O Brother, Where Art Thou? soundtrack got not only an Album of the Year trophy, but also Single of the Year for Man of Constant Sorrow, despite the fact that the record never cracked the Top 40. (The Song of the Year in 2001? Murder on Music Row, in case the powers that be hadn't gotten the message.)

And then there was 2003, when the recently deceased Johnny Cash got three final honors: Album, Song and Music Video of the Year. You could also make the case that Keith Urban's EOTY win in 2005 -- the year the CMAs were held at Madison Square Garden -- were the premature crowning of a superstar as a way of interrupting Kenny Chesney's string of wins and trying to look sophisticated in front of a New York audience.

I don't know that I've ever seen the discontent extend as deeply into the nomination process as it did this year. That doesn't mean Carrie should have gotten the snub -- she did, after all, have a top-grossing tour headlining arenas -- and Whitney's theories likely play into the scenario, too. But when that sort of thing does happen, deserving artists get left in the dust, and that's what I think happened to Carrie.