Alabama is attempting to do what no program has done in the BCS era: win a third national championship and cross the threshold into a dynasty. It has been 15 years since a program last did so. Tom Osborne, dogged for two decades as the coach who couldn't win the big one, led Nebraska to its third big one in four seasons and retired as the Cornhuskers coach.

Nick Saban could join Bear Bryant as the only coaches with three titles at Alabama. Andy Lyons/Getty Images

And now Nick Saban has brought the Crimson Tide to the precipice of matching Nebraska. No. 2 Alabama, with a defeat of No. 1 Notre Dame in the Discover BCS National Championship on Jan. 7, would become the first team to win a third national title since the BCS began in 1999.

That third crystal football is the key that will unlock the door to the pantheon of college football. We have identified eight dynasties that have ruled the sport in the modern era (beginning in 1936 with the Associated Press poll, the most widely accepted measure of a champion in the pre-BCS era). By happy accident, the dynasties spaced themselves apart, arriving at the rate of one per decade until the onset of the BCS.

The AP poll and the coaches' poll that began in 1950 provide the yardstick by which to measure a dynasty: three national championships in a several-year span, with superb records in the interim. Notre Dame (1946 to 1949) and Nebraska won their three in a four-year span, as Alabama is attempting to do. Others, such as USC (1967 to 1974), won three across several seasons.

The bottom line is that the metric of three national titles chose itself, because history has shown it's so hard to accomplish. The list of schools that won national championships in a short period of time is much lengthier.

Winning two national championships can be achieved by one extraordinary group of players. The same is technically true for winning three crystal footballs -- the Crimson Tide have 21 fourth- or fifth-year players. However, only eight, including multi-award-winning offensive lineman Barrett Jones, actually played on all three teams.

The larger truth is that for a program to win three national championships, recruiting success must be sustained over a longer period of time. Recruiting success must be sustained as coaches job-hop, as players leave early for the NFL and as opposing schools dangle greater opportunities for playing time on less successful teams.

Jerry Duncan, the president of the A Club of former Crimson Tide athletes, played for Bear Bryant from 1964 to 1966, making him a part of Alabama's first modern dynasty.