History shows not just that wars are inevitable but that we do a poor job of predicting them.

In the 1990s, a lot of otherwise smart people predicted history had come to an end. The 9/11 attacks disabused us of that idea.

Today, many military experts seem to think they know how future warfare will look. The narrative goes something like this: Large-scale wars involving huge ground forces are passe. All future wars will be combating either counterinsurgencies or terrorists. So we won’t rely as much on a navy and an army as we used to. The future belongs to drones, special operations forces and the CIA — not to tanks, infantry or bombers.

Military planners have always tended to fight the last war, and today they are no different. The temptation to do “linear thinking” in military planning is always high.

However, experts today are thinking this way from more than mere habit or intellectual laziness. The so-called “future” wars many experts predict would be a lot cheaper to prepare for. It costs less to buy more drones or organize more Navy SEAL units than it does to field more tanks, bombers or ground forces.

This is where the wishful thinking comes in. Many national security experts and policymakers expect national defense funding to be cut drastically. What better way to get out ahead of the consensus than to adopt a threat assessment that conforms to the likely budget outcome?

Unfortunately, history is a wonderful trickster. It seldom goes in a straight line. It has a way of making fools of experts who pretend to be soothsayers.

Any student of military history knows that adversaries are always looking for an advantage. That’s where terrorism and asymmetrical warfare came from. They were a way to get around the large military formations of the United States and the West.

But surely it has occurred to some military planners that if the United States decides to scale back on traditional forces — on ground and expeditionary forces, lift, nuclear weapons and naval power — even a little bit, others will find a way to take advantage of this?

To put it simply, if we build fewer tanks, others will build more. If we get out of the strategic-bomber business, thereby reducing the “triad” of strategic weapons on land, air and sea to a “diad,” other nations will be more tempted to attack our nuclear forces pre-emptively. If the reach of our naval power shrinks, however slowly, surely China — already building a larger navy — will press harder in the South China Sea and perhaps even beyond.

In other words, we are inviting other nations to get into the business of preparing more for traditional warfare. Forget the blithe talk about how we enjoy such military superiority that we can beat everyone around the world regardless of how much we cut. Our military superiority is our strategic advantage, and that is the key to our security. It is meant as a deterrent to war — to prevent anyone from attacking us in the first place. If you remove that superiority, you invite an attack and war.

Here is precisely where the danger of current conventional wisdom lies. The political debate has been set up to make it appear as if the “hard” choices are all about finding areas to cut defense.

But the real hard choice will be to decide what military capabilities the nation needs in order to deal not only with the known, but the unknown. This question scarcely arose at all during the recent debt-ceiling debate. Frankly, it is not being addressed seriously by the Obama administration.

Responsible military planners look at the array of possibilities and recommend the military capabilities needed regardless of linear threat projections.

They should not be retrofitting their assessment of future warfare to fit the conventional wisdom of budget politics.

Kim R. Holmes, a former assistant secretary of state, is a vice president at the Heritage Foundation.