Lori McKenna's "Humble and Kind" may complete the Triple Crown on Sunday. The philosophical ballad is nominated for Song of the Year at the Academy of Country Music Awards. It won the CMA award in that same category in November and took the Grammy for Best Country Song in February.

"Humble and Kind" would become the ninth song to sweep all three of these awards. It would become just the second song written single-handedly by a female songwriter to achieve the feat. The first was Jennifer Nettles' "Stay."

Tim McGraw's recording of "Humble and Kind" was a #1 country hit. If the song completes the Triple Crown, it would become the second song that McGraw made famous to do so. McGraw's 2004 smash "Live like You Were Dying" also won all three awards. (McGraw, seen at left congratulating McKenna, would become the first artist to popularize more than one Triple Crown winner.)

McKenna just missed completing the Triple Crown with a different song last year. The Little Big Town hit "Girl Crush," which she co-wrote with Hillary Lindsey and Liz Rose, won the CMA and Grammy awards, but lost the ACM award to the Chris Stapleton hit "Nobody to Blame."

Here's a closer look at the eight songs that have won the Triple Crown for country songwriters. (Budding songwriters, you could do worse than study these songs. The rest of us can simply admire the high level of songcraft.)

"Behind Closed Doors" (Kenny O'Dell). In April 1973, this sensuous ballad became Charlie Rich's first #1 country hit. (While it doesn't affect the Triple Crown status, which is based strictly on the three aforementioned country songwriting awards, "Behind Closed Doors" also received Grammy noms in the all-genre Record and Song of the Year categories.)

"Forever and Ever, Amen" (Paul Overstreet, Don Schlitz). Randy Travis took this courtly ballad to #1 on the country chart in June 1987. The song, a pledge of lifelong fidelity, contains this memorable lyric: "As long as old men sit and talk about the weather/As long as old women sit and talk about old men." Schlitz borrowed the title from the end of The Lord's Prayer, which his son was learning at the time.

"Where've You Been" (Don Henry, Jon Vezner). This tender and touching ballad was a Top 10 country hit for Kathy Mattea in February 1990. Vezner, Mattea's husband, based the song on a true story about his grandparents. Mattea had 14 higher-charting hits, but this one made a deep impression.

"I Still Believe in You" (Vince Gill, John Barlow Jarvis). In September 1992, this became Gill's first #1 country hit. It was the first Triple Crown winner that was written or co-written by the artist who made it famous.

"I Hope You Dance" (Mark D. Sanders, Tia Sillers). In July 2000, this became Lee Ann Womack's first (and to date, only) #1 country hit. This was the first Triple Crown winner that was written or co-written by a woman. Like "Humble and Kind," the song expresses simple, but profound, truths—here, in the framework of a mother's wishes for her child. "I Hope You Dance" also received a Grammy nom in the all-genre Song of the Year category—as did the next two songs on this list.

"Where Were You (When the World Stopped Turning)" (Alan Jackson). Jackson struck just the right tone on this tender, reflective ballad. It's not political or opinionated. It mostly just poses questions. The song topped the country chart in December 2001, just three months after the events of 9/11, which inspired it. Jackson adapts a famous line from the New Testament ("Faith, hope and love are some good things He gave us/And the greatest is love").

"Live Like You Were Dying" (Tim Nichols/Craig Wiseman). If you knew your days were numbered, what would you do differently? That was the idea behind this song, which McGraw took to the top of the country chart in July 2004.

"Stay" (Jennifer Nettles). Here's a cheating song which was written from the perspective of the other woman. Sugarland's anguished recording of the song (which was a powerful showcase for Nettles) reached #2 on the country chart in January 2008.

"Humble and Kind" faces strong competition for the Song of the Year prize at the ACMs. Lindsey, who collaborated with McKenna on "Girl Crush," may spoil McKenna's Triple Crown chances. Lindsey is competing this year with the Keith Urban hit "Blue Ain't Your Color," which she co-wrote with Clint Lagerberg and Steven Lee Olsen.

The other nominees are the Thomas Rhett hit "Die a Happy Man" (which Rhett co-wrote with Joe Spargur and Sean Douglas); the Miranda Lambert hit "Vice" (which Lambert co-wrote with Josh Osborne and Shane McAnally); the Eric Church featuring Rhiannon Giddens hit "Kill a Word" (which Church co-wrote with Jeff Hyde and Luke Dick); and the Stapleton hit "Tennessee Whiskey" (written by Dean Dillon and Linda Hargrove).