It may have been poor oversight in maintaining a strong D, but you can't say it was the name of our existence when it got us to 12-0 months after what you are talking about
Defense has been the Achilles heel.
From 2010 the "D" got better each year building up to 2012. The '11 unit was solid as well. Under kelly the defense has really struggled the last two years, especially under BVG.
That was the exception, not the rule.
And even then--the 2012 D was shredded by Alabama when it really counted.
Defense has been ND's bane for many years. Even going back to the Holtz years....think BC in '93 when the D shit the bed and cost ND a Title.