At least one of the following is true: (1) the American Idol franchise on the wane; (2) the Idol 3 cast is less appealing than the Idol 2 cast; or (3) soul classics are less appealing to the Idol audience than love songs or greatest moments. But which one(s)?

The American Idol 3 cast album, entitled Greatest Soul Classics and featuring performances by all 12 finalists, debuted at #10 on the Nielsen SoundScan U.S. Album Sales chart (also known as the Billboard 200) for the week ended May 2. The CD sold 55,300 copies in its debut week.

However, Greatest Soul Classics sold only about 55% of the 101,225 units rung up by its predecessor, American Idol 2: All-Time Classic American Love Songs, in its debut at #2 on the U.S. charts for the week ended May 4, 2003. It also sold only about 38% of the 146,000 units sold by American Idol: Greatest Moments, which debuted at #4 for the week ended October 6, 2002 -- but that comparison is skewed since the Idol 1 disk, released after the end of the show, featured four songs from winner Kelly Clarkson, including both sides of her #1 hit single 'A Moment Like This' / 'Before Your Love.' By contrast, the Idol 2 and Idol 3 albums only feature one song from each finalist.

The significant decline in sales from Season 2 to Season 3 may reflect the fact that viewers never seemed as "taken" with any of the current crop of contestants as they were with Clay Aiken, Ruben Studdard and Kimberley Locke last time. LaToya London continues to be the overwhelming favorite ro win Idol 3, but any one of the other three contestants remaining could finish second or fourth without much popular outcry -- a signifcant change from the reaction to Jennifer Hudson's untimely boot earlier in the season.

Another theory for the disappointing sales might be that soul classics don't sell as well to Idol's viewer base -- especially since the newest "soul classic" in this set is "Until You Come Back to Me," a hit for Aretha Franklin in 1974, before any of the singers were born. We admit to cringing at the thought of Jon Peter Lewis trying to follow in the great David Ruffin's footsteps on 'My Girl.'

Or, it might just be that the American Idol franchise is declining, little by little. But we won't know which of these possible answers is closest to the truth until American Idol 4.