The struggle played out on college football fields in California and Texas last fall, at offseason awards presentations in Florida and inside a theater room in New York City. This year's great draft debate took the top two quarterbacks to Indianapolis for the annual scouting combine and back to their college campuses for personal workouts and interviews.
Now, barring some unforeseen circumstance before Thursday night's NFL draft, commissioner Roger Goodell will declare Luck the winner when the Colts make him the first overall pick. The truth is, there may not be a loser in this competition.
"Both guys have tremendous intangibles and their skill sets are outstanding," Colts general manager Ryan Grigson said earlier this week. "I don't see how either of them are not successful in this league."
In the NFL world, there's no such thing as a sure bet. Just ask JaMarcus Russell or Ryan Leaf.
Most analysts believe, however, Luck and Griffin will be smart picks if they can stay healthy and their teams remain patient with their development.
He's smart, loves the game and leaves nothing to chance. Even their paths to the draft are similar.
Like Manning, Luck grew up with an NFL-playing quarterback father. Like Manning, Luck left his home state to play college football. Like Manning, Luck ignored the temptation to leave school after three years even though both would have been the No. 1 pick. Like Manning, Luck finished second in the Heisman Trophy race during his final college season, and the Colts are hoping that, like Manning, Luck will make the Colts a regular Super Bowl contender.
So after 14 mostly successful seasons under Manning, the Colts have decided to go with the next best thing - Luck.
Polian and the offensive coaches studied every throw those two made in college. Then, after interviewing both at the combine, Polian and the coaches each came up with an assessment. The GM then asked the late Bill Walsh to weigh in.
Yet it wasn't until the personal workouts that Polian said he was convinced Manning was the right guy - the same stage at which the Colts made up their minds about Luck.
At that point, the Colts contingent already was impressed by Luck's decision to throw into the wind at Stanford, giving scouts insight not only into Luck's ability but also his mental makeup. The message was that Luck, who is on schedule to earn an architectural degree, wouldn't let outside conditions or blitzing defenses dictate what he does.
"You have to go into it with amnesia when you really start getting into it because you want an open mind and not be influenced by outside sources and those sorts of things," Irsay said.
Luck also comes from a pro-style offense, the kind he is likely to run in Indianapolis, and his successes are hard to match.
In three seasons under Luck, the Cardinal went from a sub-.500 team to national championship contender. He broke John Elway's school record for most TD passes in a career and last season completed 70 percent of his passes while throwing only nine interceptions.
Still, Luck felt he had something to prove at his pro day.
"Just that I can make NFL throws," he said then. "Whether it's timing, the skinny post to the right, the quick out or the deep ball. Just tried to cover all the bases."
Griffin's resume is every bit as impressive.
In 2011, the Texas prep star who opted to stay home for college, threw for 4,293 yards, 37 TDs, completed 72.4 percent of his passes and threw just six interceptions - better numbers than Luck. His incredible mobility drew raves, too.
And after throwing for 479 yards and four TDs in a win that knocked Oklahoma out of the national title chase, Griffin burst onto the national scene as a Heisman contender. Eventually, he beat Luck in that one.
But NFL scouts knew Griffin was a star much earlier.
"RG3 was an unknown quantity to those outside the professional scouting community. So his `ride; was purely a result of those who didn't know him," Polian said. "He hasn't risen, he was there all the time. Anybody who tells you he wasn't, wasn't doing their homework."
Like Luck, Griffin has demonstrated there's more to life than football.
At the 2011 NCAA convention, NCAA president Mark Emmert singled out Griffin as an example of a model student-athlete.
Griffin earned his political science degree in three years, graduating in 2010. He was regular on Baylor's dean's list and still has aspirations of attending law school. He was fast enough to qualify for the 2008 Olympics trials semifinals in the 400-meter hurdles and passionate enough about volunteering to find time to help five charities.
So when Griffin decided to leave school early, it was because he felt it was time - not because of the money.
"Sometimes you just have that feeling, and I had it after the bowl game," Griffin said when he declared for the draft after resuscitating Baylor's football program. "Like I said, it's been real exciting here at Baylor, it's been a lot of fun. And in life, that's what you try to do, you try to be happy, you try to have a lot of fun."
The Redskins think Griffin is a perfect fit in Washington, right down to that political science degree.
GM Bruce Allen and coach Mike Shanahan were so convinced about Griffin's ability that they paid a hefty price to get a shot at him. They traded this year's first and second-round picks and first-rounders in each of the next two years to St. Louis to move up four spots to get either Luck or Griffin.
Shanahan understands what that kind of move that can do for a franchise. He won two Super Bowls with Elway in Denver, but hasn't been back to the NFL's big game since Elway retired after the 1998 season. Griffin could be just the guy to change that.
"You get someone you feel like can be a franchise quarterback for years to come, that doesn't happen very often," Shanahan said at the recent league meetings. "To have that guy - they're hard to find."
The next debate will be about who is more ready to win?
Luck has drawn the obvious comparisons to Elway and has been called the most NFL-ready quarterback since Manning entered the league in 1998.
Oliver Luck, Andrew's dad, insists the extra year has made his son a better, more mature quarterback.
"I think he grew in his role as a QB, I think he played in a little bit of fish bowl because of the expectations, which I think is great training for the NFL," he said.
However, Polian thinks Griffin will win the next round.
"I believe without question, both will be successful," Polian said. "I believe Andrew may struggle early simply because of the surrounding cast playing with him. It was nowhere near where Peyton's was and he went 3-13. I think Andrew will struggle more because of the receivers around him. Only Reggie (Wayne) and Austin (Collie) are back. RGIII is going to be adapting to a new offense. In spite of that, he may have the easier road in his rookie year. Having said that, they'll both struggle, but that doesn't change my opinion. I think both will be successful."
Associated Press Sports Writers Antonio Gonzalez in San Francisco, Stephen Hawkins in Dallas and Joseph White in Washington also contributed to this report.