I would add that Russian bombers are allowed to be in international air space. The question is, where do you intercept them?
Do you want to create a huge diplomatic incident when you're over international airspace, or do you want to also vary when you detect and deter these Bear bombers? If you do the exact same thing every time, that falls into a pattern, and that can be exploited. You heard from General St. Amand, there are rules of engagement, and they make decisions about when and where is best to intercept them.
The fact that it was 40 miles means people will focus on that, but that's not the point to focus on. The fact is it was deterred, it was detected, and in a statement by Admiral Gortney to the Committee on Armed Services, he said this is not new.
We saw a considerable drop-off of this activity by the Russians in the 1990s and early 2000s, but this is exactly what NORAD is charged to do, and it's doing it.