I spent my Canadian Army career as an armoured cavalry officer and was the last commander of Canada’s only tank regiment when we repatriated our troops out of Germany in 1994. Canada has recently woken up from its sleepwalk through history and decided to spend great gobs of money on rearming the Canadian Armed Forces (CAF). Along with new ships and new fighter aircraft, the CAF has decided to buy new Main Battle Tanks (MBT). Hallelujah, we all say, but which tank? The knee-jerk reaction is inevitably that we need the newest behemoth with LOTS of armour and the biggest gun available. But is this correct?

Here is my opinion. Let me be clear and state that I have not done a deep scientific dive to get all the statistics 100% correct and that is why I stress that this is an opinion piece. That said, I have spent the last half century studying, training for, and thinking about tank warfare, and even though I love all of the MBTs that have 120mm guns, after deep consideration I have come to the conclusion that we have gone too far, and that a lighter tank with a smaller calibre gun should be what future tank units should buy.

This may sound like a step backward; it may even sound heretical, but to quote an Americanism: sacred cows make the best hamburgers. It has long been an article of faith among tank commanders that bigger is better. Why would you want to go looking for a fight with less than the biggest tank? Good question. Let’s parse it. Do MBTs really go looking for a fight? It might appear so, but that is only one of the many jobs that MBTs perform. In every practical application of armour, what tanks do is integrate into a combined arms team so that, with other members of that fighting force, they can destroy any enemy — whatever it is.

The universally acknowledged article of faith is for MBTs to be effective they need to be big, and they need to pack the largest possible main gun. But that’s not a fact. It is an allegation that it feels like a fact because it is repeated so often.

If bigger isn’t necessarily better, then what is? In order to answer this fundamental question, we need to reconsider what MBTs bring to the fight. All MBTs are predicated on three design parameters: survivability, firepower, and mobility. This design triumvirate governs every modern tank ever built and is immutable. Striking an equilibrium among these considerations is no simple task, and depending on the role, the country, the national culture, and a menu of other restraints and constraints, each MBT evolves to become something slightly different. For instance, compares the US Army Abrams with the German Leopard 2. The former stressed crew survivability, while the latter stressed agility on the battlefield. Sporting variants of the same 120 mm cannon with interchangeable ammunition, these MBTs were very similar — but not identical.

MBTs must always fight as members of a combined armed force. MBTs on their own have amazing striking power and shock action but they are highly vulnerable to infantry and anti-tank forces. So, tanks need to balance the above three design parameters, and also be designed to work within a team comprising infantry, engineers, artillery, and combat aviation.

We in the armour community have for too long focused too narrowly on what we would like: big guns, lots of armour protection and lots of horsepower. All three cannot be had at the same time and so we have fallen into an intellectual trap of sorts. In scientific terms, what we in the armour community have created is a mono culture and like all monocultures, it has potentially catastrophic flaws. The problem with all monocultures is when you optimize for a single variable, you create a system that is vulnerable to the moment when that variable stops being the right one to actually optimize for. In the case of MBTs, it is size. We have inadvertently optimized for size, having convinced ourselves that the bigger the tank, the better it is for the creation and employment of combat power.

That’s wrong.