As a follow-up to my recent piece on differences between the modern world and the world on the eve of World War 1, Noel and I discussed how a modern great power war might play out in the near-future and what it might look like. Obviously, there are a lot of factors to consider (not least among them being who would fight whom, when, and over what), and for that reason I must warn that what follows should be read as little more than (barely) informed speculation. Nevertheless, I think we can make a few guesses about the nature of major warfare in the 2020s and possibly beyond.
We are largely leaving nuclear weapons out of this discussion. There is, in fact, reason to do so: there is a rich literature on nuclear deterrence, enough to show that the concept is not as simple as it appears, and although there is a consensus that nuclear weapons deter something, it is not always clear what that something is: the questions of credibility and probability involved are not simple. Suffice it to say that, as long as neither side of a major war involving nuclear combatants appeared to be in extremis with no hope of survival, it is quite possible that mutual deterrence would be enough to keep nuclear weapons from being used, at least initially. But more importantly, forgetting about nuclear weapons for a moment allows us to look at the other factors involved and see what they imply.
Without necessarily predicting exactly where conflict might erupt, we can probably predict a few things about how it would unfold. We can speculate that it would proceed in roughly four distinct stages.
Stage 1: Rapid attrition. In the past two World Wars, it was actually the norm for the combatants to fail to knock each other out of the fight initially. The great exception appears to be France, which suffered what can only be described as a total knockout in the first round of World War 2. In all other cases, although one side or the other might make some gains, it usually failed to completely destroy its opponent. One could point to the Battle of Britain, operations on the Russian Front in 1941, initial Japanese gains in the Pacific after Pearl Harbor, the stalemate on the Marne in September 1914, the inability of Germany to eliminate Russia after its victories at Tannenberg and the Masurian Lakes at about the same time, and so on.
There are reasons for this. In many cases, the wrong set of assumptions was in play: Germany, for example, did not begin serious industrial mobilization in World War 2 until after Stalingrad (arguably, after it had already lost), trusting in the ability of the blitzkrieg to deliver quick and decisive battlefield victories. In other cases, it simply took time for resources to become available: Britain, which had always focused as much of its defense budget as possible on its navy, entered World War 1 with a professional army (the crack units in the British Expeditionary Force, who, according to legend, fired their rifles so rapidly as to appear to be using machine-guns), only to enroll large numbers of after hostilities commenced (the so-called “Kitchener Battalions” that were slaughtered on the Somme two years later). In all such cases, however, the great powers were close enough to evenly matched to be able to survive the initial shock and awe.
This scenario would probably prevail in the world of the 2020s. (Right now, the United States has a good chance of achieving a rapid knockout blow in a conventional conflict.) The trend towards professionalization (absence of conscription in most big states) and reliance on high technology (the inflation-adjusted costs of major weapons systems being significantly higher than in past wars), combined with the likelihood that at least one side would not have a long warning time prior to the onset of hostilities suggests that replacing lost equipment and personnel would require more mobilization and preparation than either side would likely have at the start of conflict.
In other words, unless one side or the other prevails decisively in the first weeks of the war, the initial forces of both sides are likely to be destroyed. Let’s first consider personnel. Most modern militaries invest large sums of money and large quantities of time in training their personnel. That makes lost personnel difficult to replace, particularly in the absence of conscription, which few states (and no great powers except Russia) employ. For that matter, mass conscription by definition implies sacrificing quality for quantity: professional armies throughout history have invested more training resources in each individual soldier, sailor, or airman than militaries based on mass conscription. The IDF and South Korea are partial exceptions, but those are armies geared for territorial defense (and in Israel, occupation of hostile territory) not expeditionary warfare.
The size of modern armies is small for this reason: in terms of military participation rates, the modern great powers are closer to medieval kingdoms than to pre-World War 1 states. (Modern great powers have less than 1% of their populations in the military, including reserves, compared to 5% of European populations on the muster rolls in 1914.) Although some of this reflects a choice (conscious or unconscious) some of it is a function of technology and the time it takes to learn to use it. It is quite debatable whether a modern state could replace combat pilots, for example, at the same rate as Britain and Germany did in 1940 — even allowing for the fact that both countries tolerated a much lower standard of proficiency than the prewar norm.
What applies to personnel applies even more strongly to equipment. At least as of now, modern weapons systems are a boutique industry. The days in which aircraft carriers could be repaired in a few months and fighters mass-produced in converted automobile factories are effectively over. In theory, mass production of modern weapons systems is possible. Lockheed-Martin, the producer of the much-maligned, exorbitantly expensive F-35, has claimed that with sufficient orders, economies of scale and an assembly line-style plant you could produce one F-35 per working day. This is still a slower piece rate than the production of, say, P-51s in World War 2, but it might pass muster for wartime purposes.
If you stop to think about it, though, the numbers do not add up. It was expected during the Cold War that a major confrontation with the USSR would result in the destruction of the US Air Force’s entire A-10 fleet within two weeks of continuous combat — rather shorter than, say, the Battle of Britain, where it took something between four and sixteen weeks (depending on your definition) to grind down the Luftwaffe — and the Battle of Britain still left the combatants with air forces. It is an open question how long it would take to set up new factories to ramp up production of the F-35. And even if we did, 365 aircraft a year is not a very large number. What applies to aircraft applies even more strongly to ships: modern aircraft carriers take seven years to build (compare one year to build HMS Dreadnought before World War One or less than two years to build an Essex-class carrier in World War Two). Some of these build times could be cut short via a crash program or economies of scale associated with wartime mobilization and production — but not right away.
It is therefore likely that, once it was clear that neither side had achieved complete superiority over the other in the immediate opening of the war (whether at land or at sea) attrition would result in the destruction of equipment faster than it could initially be replaced. This would be especially true of the air war, since aerial combat is attrition par excellence.
In short, Stage 1 would pit professional militaries with high-tech weaponry against each other. The high-tech weaponry will be subjected to merciless attrition and destroyed without replacement in the first week or two of the war. Destruction is a lot easier than creation, so most of the high-tech weaponry that Western militaries in particular rely on disappears and the states that rely on it have to go to plan B.
This would bring us to ...
Stage 2: Stalemate. The destruction of equipment and loss of trained personnel would probably lead to a lull in the fighting. (Tom Clancy envisioned something like this in his now-famous fictional story, Red Storm Rising, in which a conventional conflict in Europe between the West and the Soviet Union bogged down into a stalemate after a few weeks.) Both sides would have to look for new reserves of manpower and equipment to continue the fighting; depending on how unprepared they were at the start of the war, this might take weeks or years.
In such a circumstance, negotiation might be inevitable. This was not the norm during the World Wars — neither in World War 1 after the war had bogged down in the trenches, nor in World War 2 after the blitzkrieg had failed to defeat Russia, was there much impetus for a diplomatic solution. In an older, richer, and more peace-loving world, though, the exhaustion of immediately available resources might lead one side or the other to consider coming to the table. (When Foreign Policy discussed a hypothetical Sino-Japanese War of 2014, they came to the conclusion that a stalemate was likely ... which in that case meant an effective Japanese victory, since China would have little incentive to press the war further.)
It is probable the U.S. would not follow this pattern. The experience of Korea, Vietnam, and Iraq has shown that even when a war is divisive, unpopular, and not going well, there is usually enough political will to fight to overcome opposition to the war for several years. It is an open question, however, what would happen if the will to fight existed but the means to continue could not be found right away.
If they could, though, things would probably go to ...
Stage 3: Mobilization. As noted, when great powers expect a quick war and do not get it, they historically have geared up for a longer struggle. And, as noted, this will be much harder in an era when militaries are more dependent on expensive and hard-to-replace technology than before. It is also probably more difficult in an era in which states have less slack capacity: when states spend a larger percentage of their GDP than in the era of the World Wars on providing services to their populations, who have come to expect those services and in fact have paid taxes that they cannot get back for them, and when those states also have aging populations in greater need than in the past of healthcare and related services, and again when those states in many cases have unusually high levels of private debt that their populations expected to be able to service, those states’ populations are likely to be more sensitive than in the past to fluctuations in the government’s ability to care for them. That said, there are many ways to finance a war effort, including, but not limited to, debt, taxation, inflation, and directly commandeering hard assets and resources (including rationing necessities and raw materials). With the possible exception of inflation, all of them would likely be more challenging in the modern era.
We have some experience to draw on here: as mentioned earlier, the German practice in World War 2 was to avoid full-fledged industrial mobilization until Stalingrad. Something similar is likely to happen in a future war.
This is when some states that kept fighting after Stage 2 will opt out — the costs are too high. But even for those that remain, many combatants will have little to fall back on. Nuclear-powered aircraft carriers, supersonic stealth fighters, and main battle tanks don't just materialize out of thin air, and repairs to damaged ones take a while. Whatever the belligerents come up with is going to be low-tech, ad-hoc, and inexpensive, to the extent practicable. This might knock the U.S. out of the fight just for that reason: even if you solve the technical problems, getting the necessary equipment across the ocean to fight might be tricky, depending on expenses. It might also lead to all sorts of interesting innovations. Cheap slow mass drone assaults? Self-driving kamikaze cars? PT boats armed with modern missiles?
The other mainstay of large-scale mobilization, conscription, will be less useful than in the past. (Note that “less useful” ≠ useless.) The reason, again, is the modern reliance on expensive technology. Put differently, obtaining World War 2 levels of military participation assumes that they will be transported and supported by World War 2-style aircraft and ships and ride in World War 2-style vehicles. An M4 Sherman tank cost about $715,000 in 2013 dollars; a modern M1 Abrams costs about $8.6 million. A World War 2-era P-51 cost about $700,000 in 2014 dollars, compared to anything up to $150 million for an F-35. Even an F-16, one of America’s more cost-effective fighters, cost $19 million in the 1990s when the current fleet was built and would cost about $27 million today.
At the height of the Iraq war, a common gripe among recent veterans ran “We’re at war; America’s at the mall.” Something similar might prevail in at least some great powers in in the early parts of Stage 3 and the political effects could skew either way. The war might become easier to sustain (because of fewer casualties) or harder to sustain (because of a lack of desire for revenge for family members killed in action, combined with discomfort with the economic costs of mobilization).
Nonetheless, if Stage 3 lasted for any length of time some sort of limited conscription would be likely. The U.S. military faced severe recruiting problems by the end of the Iraq War; it is not clear that new volunteers would be enough to fill the gap in a future prolonged conflict. In addition, governments may want to conscript civilians with skills useful for the war effort. Finally, conscription is a cheap way to save on manpower costs, at least from the point of view of the government’s cash flow. Draftees are generally cheaper than volunteers.
That said, conscription on the scale of the world wars is unlikely. It is hard to see why the U.S. would need, say, to put 27 million Americans under arms — the current equivalent percentage of Americans as the U.S. had in uniform in 1945. Even 7.0 million (the equivalent of the current active-duty Israeli Defense Force) or 5.5 million (the equivalent of the U.S. active-duty military at the 1968 height of the Vietnam War) seems unlikely at this stage, at least for the United States. (Other countries, gearing up for potential invasion with most of their initial high-tech kit in shreds from Stage 1, might have different incentives.)
But at least part of the war might become manpower-intensive in due course, because as territory changed hands, it might well progress to ...
Stage 4: Insurgency. Large territories with hostile populations have been known to swallow great powers in the past, as Afghanistan, Vietnam, and Algeria have shown. Ironically, the Truman Administration’s decision not to intervene militarily to stop Mao from taking over China amounted to a decision to avoid the same scenario the U.S. bungled into a decade and a half later in Vietnam. Particularly when a government has had some warning, it can lay a deadly trap for a would-be invader. Finnish ski-mobile light infantry surrounded and cut off Russian armored columns during the Russo-Finnish “Winter War” of 1939-40, effectively stymying the Russian advance and forcing Russia to stop short of total conquest. The Fedayeen Saddam menaced U.S. supply lines during the invasion of Iraq, and it has been noted that the fighting around Al-Nasiriyah in the very early stages of the invasion already resembled the insurgency that followed, with U.S. forces facing irregulars as well as the Iraqi military. A little more preparation could have made for an even deadlier insurgency from the outset.
Some of the tactics of modern mass opposition depend on global political norms and interaction with global media that can condemn a conqueror’s actions and urge democratic states not to legitimize them; this sort of help could not be taken for granted in a world conflict in which global norms had broken down and the political stakes were higher. This might point toward an insurgency based more on classic paramilitary or guerrilla opposition rather than mass protest, and for that reason the conflict in the areas taken by one side or the other might be even more violent. As long as weapons and supplies could get to insurgents, such a conflict could continue indefinitely, span a wide geographic area, and involve large numbers of participants.
Policing such an area in the home territory of a large great power would involve more manpower than could be had via normal enlistment and would therefore require conscription — as Vietnam and Afghanistan have showed, such a scenario rarely ends well for the occupying state, even if something like success is achieved.
If exhaustion of available resources without military success failed to end the conflict, and if the problems of military mobilization in a modern state likewise did not force states to the table, the prospect of a “forever war” in a vast geographic area with a large population for minimal gain, while still having to face a conventional opponent on the front lines, almost certainly would. Nuclear weapons would not even have to come into play — sheer exhaustion might be sufficient.
Global wars often look futile in retrospect — for every World War 2, there is a World War 1. One suspects that, even without the prospect of a nuclear exchange, a future world war might come to be viewed as very futile indeed.