Let me start with two observations on the assumptions.
One, I think the focus is even more narrow because I don't think we've really focused on counter-insurgency against a committed enemy under occupation as opposed to COIN in support of a mostly friendly state and allied government.
Two, I don't think that the Donbas is really a case of Russia waging a proxy war as much as it is a subliminal war where Russia has invaded--with local allies, to be sure--with its own troops and mercenaries, while denying it has invaded.
But back to proxy wars:
A proxy war is favorable for a variety of reasons, but most notably, it provides the principal actors a degree of standoff and limited liability. Retired Lt. Gen. H. R. McMaster reflected on this phenomenon while discussing the Mutual of Omaha’s Wild Kingdom fallacy, one of his many works on the continuities and changes of future war. The fallacy posits that the U.S. military, and more specifically, the U.S. Army, can empower other forces—proxies—to do its fighting, just as Wild Kingdom host Marlin Perkins would have his assistants do the close-in work with the dangerous animals on the show. The problem with outsourcing fighting to proxies, as McMaster noted, is that these forces often are insufficiently resourced and possess limited will due to dissimilar interests.4 McMaster only scratches the surface of proxy hot spots, but his position serves as a point for starting the discussion.
Given the ubiquitous nature of proxy environments, the U.S. Army demonstrates a poor understanding of how to achieve success within these environments. The U.S. Army has achieved a modicum of success in Iraq (2014–2018) and the Philippines (2017), but its overall track record in proxy hot spots, including Afghanistan (2001–present), Iraq (2003–2011), and Syria (2014–present), illustrate this point. Notwithstanding the absence of empirical research, one can surmise that the U.S. Army poorly performs in these environments because it lacks a taxonomy for understanding proxy warfare. Furthermore, contemporary parlance obfuscates the true character of proxy hot spots through the use of terminology like security force assistance, advise and assist, and related language.
To take the argument a step further, the U.S. Army is ill-suited for warfare in the proxy environment because it mismanages the fixed time and the finite power it possesses over a proxy force in pursuit of waning mutual interests.
I have a problem with this list of proxy campaigns. One, you could add in a Philippines proxy war begun just after 9/11.
You'd have to cut out the proxy designation for Afghanistan from 2009 to 2011 or 2012 during our surges of American and coalition forces to take the lead in fighting.
I'd argue that you'd also have to cut out the American campaign in Afghanistan in 2001 and early 2002 because while we relied on local allies, we were overtly and obviously involved. If you do include Afghanistan for this period as a proxy war--and you certainly can if deniablity isn't part of your definition of proxy warfare--then you'd best split Afghanistan into the initial war against the Taliban government and the subsequent war against the Taliban insurgency.
And you'd have to adjust the starting point of proxy warfare in the original Iraq War to 2009 when shifted formally to advise and assist after our Surge offensive and Awakening essentially won the US-led portion of the war; and extend the end point from 2011 when we withdrew from Iraq to mid-2014 when ISIL overran large parts of Sunni Arab Iraq. Although I suppose you could argue that 2011 is better because it represents an effective end of an attempt to win through proxies and is better called an abandonment of any strategy to win except to hope that Iraq would win essentially on their own.
As for Syria, yeah, the problem of waning mutual interests was always obvious in the US-Syrian Kurd alliance. We had a mutual interest in defeating ISIL but once that was largely done (and the end game for the last scraps of the caliphate's defeat is taking place as surviving jihadis give up in larger numbers) the Kurds had no interest in taking on Assad and we had no interest in fighting for Kurdish independence in the face of competing regional interests. Interests diverge. What we do then?
How is the argued mismanagement of fixed time present? Who fixes the time (isn't that a function of the civilian government and not in the military's lane?) and why would you put an artificial time limit on a proxy war where more time is required because of the more limited power made available? If you have limited time, proxy warfare shouldn't be the answer to the problem.
And this has to be different than the Cold War concept when battles between Western-backed states and Soviet-backed states were called "proxy wars."
How are local allies inherently more limited in their will to win than we are far from home? Certainly, differing objectives is a problem. As I've said in a broader context, when you "lead from behind" other countries may simply act in their own interests rather than follow from the front. So use of proxies is not a matter of them having less will to win than we have--although they may have less will to win our objective because they develop different objectives.
But if they are less capable of providing us with decisive results we have to accept that they are also less capable of providing our enemies who use proxy warfare with decisive results.
Really, isn't proxy warfare a sign of weakness? Don't you use proxy warfare when you either can't openly and directly fight or won't--because of the cost or the risk of getting in a bigger open fight you can't win?
I really want a better definition of what a proxy war is. It can't just be a different term for having local allies, which the author recognizes.
But yeah, as long as Russia is too weak to send in the tank armies we should study proxy wars more.