Tom Brady versus Bill Belichick

— -- Even in the churning vortex of the NFL, Rodney Harrison was always a fearless operator. He played safety with unusual ferocity for 15 seasons, the last six with the New England Patriots (2003-08). There wasn't a tight end sprinting across the middle or a running back blowing through the line he wouldn't try to tackle.

But tackling this gnawing question, well, this one has him seriously flummoxed.

"Oh," he said recently, pausing. "That's -- that's tough."

Harrison, in his sixth season with NBC's "Football Night in America," is part of the broadcast crew for Super Bowl XLIX. In the coming days, you'll probably see the two-time Super Bowl champion discussing the unprecedented success of Bill Belichick and Tom Brady, his former head coach and quarterback, but there is one thing you won't hear.

He refuses to place one above the other.

"Obviously, Bill Belichick jump-started Tom Brady's career," Harrison said. "Yeah, we'll put Drew Bledsoe and his $100 million contract on the bench and keep this sixth-round draft choice as the quarterback. It shows you the type of balls this guy has. To be honest, [I was told] it was split in the locker room.

"But to me, Tom Brady and Bill Belichick are tied at the top. I believe that one guy wouldn't have had all that success without the other. I would never pick one. Never."

Still, it's a tantalizing debate: Who is more responsible for the Patriots' parity-bending, bottom-line achievements in Belichick and Brady's 15 years together?

Belichick has more playoff victories 21 (20 with the Pats and one in Cleveland) than any coach in NFL history. Brady has won more playoff games (20) than any quarterback. Sunday's game in Glendale, Arizona, will be their record sixth Super Bowl together. How do you separate the inseparable? Who's better at his job? Bill Bradichick or Tom Belady?

In a sense, it's an unknowable, unquantifiable question, a task like trying to split the atom or discover the culture that created those statues on Easter Island. The chicken or the egg -- which came first? Which child is your favorite? Ugh.

As a public service -- and a freakishly fun forensic exercise -- we checked in with more than two dozen knowledgeable sources in and around the game of football who've dealt with these two over the years. The results might surprise you.

Brady 0, Belichick 0, Push 1

Conception versus execution

A former assistant who spent considerable time with both men has a definitive opinion. Problem is, he still works in the NFL.

"I think you have to go with Bill there," he said, only after requesting anonymity. "Bill Belichick coaches the team. Bill Belichick runs the draft. Lots of guys have left the staff, and they've kept winning.

"In terms of organizational structure, what's been the same?"

The five most notable former Belichick assistants who went on to become head coaches -- Romeo Crennel, Nick Saban, Eric Mangini, Josh McDaniels and Bill O'Brien -- have won 96 regular-season games in seven head-coaching assignments -- and lost 143. That works out to a .402 winning percentage.

"If you take notes and pay attention," the former assistant said, "you're going to learn a lot. I'm not going to lie, he's very demanding to work for but also fair, smart, decisive. He knows more about football than anyone, knows more about people and their motivations. He knows more about everything than almost everyone.

"Nobody coaches a team in every facet of the game in a more complete, better way than Bill Belichick. Tom has a lot to do with it, but at the end of the day, he's one player."

Over the years, Belichick has employed a linebacker as a touchdown-catching tight end (Mike Vrabel), a wide receiver as a cornerback (Troy Brown), a defensive tackle as a lead blocker (Richard Seymour), a wide receiver as a touchdown-throwing quarterback ( Julian Edelman) and, most recently, an offensive tackle ( Nate Solder) as a touchdown-catching tight end.

Those were creative solutions to technical problems, but the videotaping scandal known as Spygate revealed what some insist is a faulty moral compass. At the very least, you can call it gamesmanship and an innate ability to seek and find loopholes. In the divisional playoffs against the  Baltimore Ravens, Belichick created an advantage by surprisingly lining up ineligible receivers, which infuriated Baltimore head coach John Harbaugh but was ruled as legal by the league.