Republican candidates have garnered a great deal of attention here for their various pronouncements on the defense budget and the state of the U.S. military. This focus on the GOP has been due in part to the fact that they have been the ones talking about defense issues, but also because what they have had to say is appalling. The Department of Defense did finally garner a mention in Sunday’s Democratic candidates’ debate, and it is worth delving further into what was said.

Taking a break from political science denialism about campaign finance for a few moments Sunday night, democratic socialist Senator Bernie Sanders declared:

We have a $600 billion military budget. It is a budget that is larger than the next eight countries. Unfortunately, much of that budget continues to go to fight the old Cold War with the Soviet Union. Very little of that budget—less than 10 percent—actually goes to fighting ISIS and international terrorism. We need to be thinking hard about making fundamental changes in the priorities of the Defense Department.

On several points Sanders is right. The United States spends a tremendous amount of money on its military, both on its own terms and in comparison to the rest of the world. He is also right that the much of the budget goes to preserve a Cold War military force structure and that “fundamental changes” are in order at the Pentagon.

The question is, what changes need to be made? Sanders cited the small percentage of the budget dedicated to fighting the Islamic State and terrorism more generally. It is unclear from the democratic candidate’s statement whether he believes this threat should become the top priority for the U.S. military. If so, the implication is that the defense budget, and the size of the military, should be oriented for counter-terrorism. Fighting terrorism does not require large-scale military forces. The invasions and occupations—and the costs associated with them—that took place following September 11th were disproportionate to any potential terrorist threat. A military postured solely to fight terrorism need not maintain an army, with only special operations forces necessary for counter-terrorism operations; only a minuscule navy would be needed for transportation purposes; and the air force might only require drones for targeted strikes against terrorist leaders or cells.

However, a military postured solely to fight terrorism is both unlikely and probably a dangerous proposition as well. While scholars such as John Mueller and Stephen Pinker have produced excellent work in recent years demonstrating the decline of major war as an instrument for settling international disputes, neither can entirely rule out the possibility of its return. For that reason, the United States is likely to maintain military forces postured for conventional war to try and deter aggression—mostly against U.S. allies given the two oceans that separate America from potential aggressors—or to fight a war should deterrence fail.

Unfortunately, many people—including most of the Republican presidential field and many conservative think tank analysts—take the mere possibility of armed conflict as a reason to drastically increase the defense budget far beyond the current levels Sanders cited Sunday night. In doing so, they assume they know the character of how a future conflict might take place. But the history of conflict is largely one of that assumption being proven wrong. Former Secretary of Defense Robert Gates himself once stated that the Pentagon was “one hundred percent right zero percent of the time” when predicting the next war. As Richard Danzig noted in a widely cited paper on the role of prediction in defense policy, human beings by their very nature strive to predict, yet they invariably prove themselves very bad at it. But that doesn’t seem to temper the desire to expend vast sums of money into an enterprise fraught with so much uncertainty.

While Sanders is likely wrong that the defense budget will be reduced commensurate to a fight against terrorism, he is right that “fundamental changes” need to take place. The United States will obviously retain conventional military capabilities at least for deterrent purposes. Change should start by recognizing that future conflict will remain possible, but unknowable, and plunging increasing amounts of money into an already bloated defense budget will ensure large amounts of financial resources will inevitably go to waste trying to pretend it is not.