The Bears are the only defense to not allow a rushing touchdown in 2018, an impressive statistic for an impressive defense.  
But in today’s NFL, which is so heavily skewed toward the importance of passing offense, how much does it really matter that the Bears have one of the league’s best run defenses?
“It’s still important because most offenses in this league, if they can bludgeon you with the run, they will,” defensive coordinator Vic Fangio said. “Now sometimes there isn’t as much patience as there used to be around the league with that. But if you’re not doing well against the run, now you start playing stuff that makes the passes even better for them. So the answer to your question is, the value of the run has gone down a little bit just because of the way teams are playing, but if it’s not there it will bother you.”
Consider this, though: The top 10 run defenses in 2018, by rushing yards allowed per game, are allowing about a point and a half more per game (22.8) than the top 10 passing defenses are (21.3). Diving into the world of advanced stats, the average overall rank of the 10 best rushing defenses by DVOA is 11th, while for the top 10 passing defenses average 7tth in overall defensive DVOA.  
The point being: It pays more to be a good passing defense than it does to be a good rushing defense. 
It’s intuitive, given the passing explosion seen in the NFL this year and the league continuing to implement rules to benefit quarterbacks and passing offenses. And that’s why Bears defensive end Roy Robertson-Harris framed the importance of a run defense like this:
“You gotta stop the run (to) earn the right to rush the passer,” Robertson-Harris said. “We all want to get sacks. (Defensive backs) want to get picks. But in order to do that, we gotta stop the run first and second down, third and short, all that — we gotta do what we can to earn that opportunity to make the plays we want to make.” 
Through eight weeks of the 2018 season, teams are averaging the fewest rushing attempts per game (25.6) the NFL has ever seen, down from a range of 26.0-26.9 from 2013-2017. The last time teams averaged 28 or more rushing attempts per game was 2006. It’s been 30 years since teams last averaged 30 or more rushing attempts per game. When the Bears won the Super Bowl, offenses averaged 30.4 rushes for 124.9 yards with one rushing touchdown per game. 
Now? Beyond those 25.6 rushing attempts, teams are averaging 111 rushing yards per game and 0.8 rushing touchdowns per game. 
“It’s not (the same),” defensive lineman Akiem Hicks said. “There aren’t guys like Casey Hampton, Vince Wilfork, Tony Siragusa — there aren’t those guys anymore. To play defensive line in this league and to be effective and play for a long time, you gotta be able to rush the passer and play the run. I think the emphasis has been taken away a little bit from guys who can just step in there and be run cloggers.”
This isn’t to say that stopping the run no longer matters. It very much still does — the Miami Dolphins hung 31 points on the Bears with Brock Osweiler as its quarterback thanks, largely, to Frank Gore gashing the Bears’ defense for 101 yards. Conversely, the New York Jets barely managed 10 points with the Bears’ smothering Isaiah Crowell and Trenton Cannon for 35 yards on 19 carries. 
The Bears invested in stopping the run, too, in drafting an inside linebacker with a top-10 pick and guaranteeing a little over $44 million to Hicks and Eddie Goldman in their respective four-year contract extensions. Muting the production of Buffalo Bills running backs LeSean McCoy and Chris Ivory will be the key to clamping down on an otherwise sub-optimal opposing offense this weekend. 
“When you have a good feeling that you can (stop the run) it frees you up mentally, meaning me, as to what we can call,” Fangio said. 
For the Bears’ defense, stopping the run not only is key from a pass rushing and defensive productivity standpoint, it’s important from a psychological one, too. There’s a certain pride factor that comes with stopping the run — usually, it means the front seven’s power and strength is beating the opposing offensive line’s power and strength. Winning that battle gives the entire defense confidence; losing it can be a tone-setter in a negative way. 
And so stopping the run remains important for the Bears’ defense, just as it is for the other 31 defenses in the NFL. It’s just not as important as it used to be. 
“If you can’t stop the run, they’ll run on you all day,” Hicks said. “And it’s demeaning to a defense.”