After years of counterinsurgency in the Middle East, the Pentagon says the biggest threat to US security is Russia. That's not just because of Russia's nuclear weapons, it's "hybrid warfare" of the sort Vladimir Putin is using in Eastern Ukraine. US troops are already training to combine counterinsurgency with conventional weapons, street-level fighting, cyber-warfare and propaganda. One very concrete example of that changing strategy took place in the Mojave Desert earlier this month in an exercise called Operation Dragon Spear. The goal is deterring Russia from moving on NATO members Latvia, Estonia and Lithuania -- or other members of the former Soviet Union.