Where Seattle's D ranks all time

— -- The Seattle Seahawks are built primarily around their suffocating Legion of Boom defense, and that defense has now driven them late into the postseason for the third straight year.

If the Seahawks win their second straight championship -- our simulations at Football Outsiders have them winning 37 percent of the time -- they will have won those two titles by vanquishing the best quarterbacks the rest of the NFL has to offer. Last year, they took out Drew Brees and Peyton Manning. This year, they'll have to take out Aaron Rodgers and then either Tom Brady or Andrew Luck.

So it's a worthwhile question to ask: Is this the best defense in NFL history? Or at the very least, the best in recent NFL history?

If we're only looking at a single regular season, then the clear answer is "no." This year, the Seahawks did finish the season at No. 1 in Football Outsiders' advanced DVOA ratings. (DVOA, which stands for defense-adjusted value over average, is explained further here.) But the Seahawks were one of the lowest-rated defenses to ever finish at No. 1, and certainly were not as good as they were a year ago.

We have play-by-play broken down to do DVOA ratings for 26 seasons, from 1989 through 2014. The 2014 Seahawks had a defensive rating of minus-16.3 percent, which ranks them behind 44 different defenses of the previous 25 seasons. The 2013 Seahawks, on the other hand, had a rating of minus-25.9 percent, which ranked seventh among all teams over that span.

However, what if we look at the Seahawks over this entire extended period rather than just one season?