The reality is that we need new laws, policies, practices, etc for more effectively deterring state actors that are not deterred by our old approaches in the current environment. We need the same for actively engaging, when necessary, short of war, to impose costs and to disrupt their actions.
I agree, our lexicon, our rules, our laws, our approaches, are hopefully outdated. In the end I don't care if we call it war, as long as we recognize it isn't peace and that what we're engaged in (or ignoring) is seriousness and requires real strategy.

We evolved from low intensity conflict (LIC), which included a spectrum of conflict from low to high intensity. That is telling, because high intensity conflict (though subjective) could include major combat between conventional forces and even nuclear weapons. Yet, we called it conflict, not war. When the Cold War ended, we transitioned to military operations other than war (MOOTW). We harped on the importance of interagency collaboration and synergy, but the further we got away from using the construct of war the more stove piped our various agencies became. We identified problems in clean little stove pipes. Oh that is a law enforcement problem, and that is a development problem, and that is a military problem, and we'll use a little information to solve that one. The military has its own problems with its definitions and reducing a problem to insurgency, terrorism, etc.

The concept of war hasn't been in vogue for decades in the U.S., because apparently it is better that we can conduct it almost persistently without calling it war. We don't have a CT strategy, we have a decapitation strategy that has been a miserable failure. We don't have a COIN strategy, we have a nation building strategy. This gets to my underlying point, why I recommend calling it war (for now). In theory, war requires a holistic strategy that is closely monitored by national security. It is not an excuse for different agencies and services to compete with each other for a slice of the national budget. If the leaders can't work with each other, then they should be fired. War is too serious for maintaining the status quo.

Moreover, I think treating some security threats with the seriousness that war deserves (e.g. al-Qaeda in 1996) would result in much less violence world wide, because we would pursue solutions instead of engaging in endless conflict due to half-hearted efforts that are not part of a coherent strategy. The old view of war as China and Russia theorists point out is not widely applicable today. In fact, they assume we're waging war, and they don't buy we're waging a messy peace. They respond appropriately, while we continue our willful blindness. Not all wars require bombers, tanks, or even major battles. If you buy into Sun Tzu, in theory you can win the war before the first shot is fired.

Why do you think we can have a messy peace, but war can be clearly defined (again you failed to define it)?