Given the anti-globalism currently overtaking politics from the United States to the Philippines, it is no surprise that many public figures in the US are considering an exit from the North Atlantic Treaty Organization, a military alliance generally referred to as NATO.

NATO was conceived during the dawn of the Cold War. Designed to contain the ambitions of the USSR, NATO’s original membership consisted of many Western European nations plus the United States and Canada. NATO is, among other things, a mutual defense pact, which is the most concrete type of military alliance. NATO’s mutual defense clause, Article 5, compels all NATO nations to come to the defense of any NATO member who is attacked. There are no obligations to aid a NATO member who begins a war themselves.

As time went on, NATO expanded, admitting more European members. After the fall of the USSR, a number of former Soviet states rushed to join the alliance. In addition to its member nations, NATO also cooperates with a number of international allies such as Australia.

In recent times, politicians and military strategists have aired their gripes with the alliance. Not long ago, an article on this site explored one of the more serious flaws in the alliance: members do not share the burden equally. More specifically, once a nation is admitted to NATO, there is no threshold of military expenditure for continued membership in the alliance, leading to what many interpret as freeloading.

Requiring accountability on behalf of all members is one thing, and alliance members should undoubtedly explore solutions to increase accountability within the organization. However, the modest flaws in NATO’s structure should not compel the United States to leave an alliance which has been critical to ensuring the stability of Europe and the world at large.

In order to appreciate the importance of NATO, one must understand what the alliance does for global security. The US military is indisputably the most powerful in the world, so naturally many ponder: why maintain a military alliance with nations such as Estonia and Montenegro when their force contributions to any US military operations would be insignificant?

The same argument could have been made on the eve of World War II. Why pledge to defend militarily-insignificant states in Eastern Europe when they would be quickly overrun by Nazi Germany or the Soviet Union? In reality, there are numerous reasons to incorporate small states into military alliances and defend collectively against aggression.

Much of NATO’s value derives from Article 5. Without a mutual defense alliance, small states have to simply hope that their neighbors will not invade or push them around. While international law and global anti-war sentiments limit militarism to an extent, one needs look no further than a list of ongoing conflicts to realize that the world is not in (and, indeed, has never been in) a state of peace. Article 5 gives small NATO members something they could never dream of having on their own: concrete military deterrent. While Poland may never be able to field a first-class military capable of defeating Russia in battle, NATO membership means Poles have a massive alliance representing 70% of the world’s military expenditure backing their border integrity. For small nations such as Lithuania, NATO is basically the only guarantee of military security.

The goal here is not to compare Russia to Nazi Germany. Rather, the events that lead up to World War II offer an insight into how small nations can be overrun by a powerful neighbor when not properly supported. Many people think of wars between countries as features of a bygone era, and thus attack NATO as outdated and useless. People of that opinion should speak with a Ukrainian. Many powerful states currently engage in warfare or aggression either outright or by proxy, and NATO deters such destabilizing conflict.

While small nations such as Estonia and Latvia may not be militarily crucial, their hypothetical fall would certainly have global repercussions.  Global financial markets would falter if any European nation were to be invaded. Foreign leaders would quake in their boots, wondering who could be next. And, most importantly, the US would be drawn in eventually. In both World War I and World War II the US thought it could watch from the sidelines, but in reality this is never the case. Better to deter aggression in the first place than to let the situation escalate into a bloody world war. The inconvenient truth is that leaving NATO to avoid wars could backfire spectacularly and actually make the US more likely to be dragged into a conflict.

By guaranteeing mutual defense, NATO makes an attack on any member virtually suicidal. Because of this, no NATO member state has been attacked by another state since the alliance’s ratification, which illustrates its immense deterrent value. As a result, Europe under NATO has been extraordinarily peaceful and the US has not had to fight wars to support NATO members.

If the US were to leave NATO, states which were formerly NATO members would suddenly be in a much weaker strategic situation, tempting others to pressure them and bait out border conflicts, which can escalate into full-scale war. This is exactly what occurred in the Ukraine, which is not a NATO member, and it could happen to many other European nations if the US were to abandon NATO. For better or for worse, the Ukraine was not seen as a crucial US ally, so there was little obligation for the US to jump to its defense. If Poland or another European state were to be invaded, the situation would be much different.

To take a more detailed look at NATO’s role in preserving stability, let us consider a hypothetical situation in which the US leaves NATO, stripping much (if not the majority) of the alliance’s military power. In such a situation, NATO might even dissolve completely.

Shortly after the US’s exit, a former NATO member in Europe has been invaded. Washington would face a choice: either go to war and defend our ally, or balk and appear weak. Neither is desirable. Both would seriously reduce global stability, damage financial markets, and likely lead to further conflict. One could counter: “At least leaving NATO gives us the choice between war and isolationism.” However, that logic is flawed: given the NATO’s track record, the hypothetical invasion likely would never have occurred had the US remained in NATO. The best option is to stay in NATO and let the deterrent value of Article 5 reign supreme.

NATO also has value beyond the mutual defense clause. Believe it or not, the US does reap military benefits from its NATO membership. For one, NATO has integrated intelligence and command structures, which make it easier to conduct operations with allies, receive intelligence promptly from NATO members, and police European airspace. While the US has formidable intelligence assets on its own, the geographical location of many NATO allies means that the US gets rapid, firsthand intelligence and forward basing locations from the Mediterranean to the Baltic.

If the US were to leave NATO, a fracturing of military procedures and international cooperation among US allies would likely result, seeing as NATO standardizes and regulates fields from communication to ballistic protection. These standards take ease of interoperability a step beyond what could be achieved outside of the NATO framework. They also allow for economies of scale and easy integration of US weapons into European militaries. Basically, if the US were to leave NATO, working with allies even in theaters such as Afghanistan and Syria would suddenly become much more difficult, and interoperability would be much more difficult were conflict to break out.

Lastly, leaving NATO would call into question the resolve of the US to deter aggression and uphold the international order; a US exit from NATO would surely prompt other nations with which the US has mutual defense pacts to reconsider their strategic situation. Apart from NATO members, many countries such as Japan and The Philippines rely on defense pacts with the US. Some of these nations are dealing with conflicts of their own, especially in the South China Sea.

A NATO exit would suggest to allies that the US is not wholly committed to their defense, which could lead to an increase in militarism and aggression among these relatively peaceful nations, ultimately further destabilizing the region and possibly requiring US intervention down the line. Again, deterrent would be put at risk: while Japan and South Korea are effectively impossible to directly attack under US mutual defense treaties, the risk of conflict would increase dramatically were the treaties to either terminate or become questionably valuable. Deterrent must be backed up by intent, or else its effect is forfeited. A US exit from NATO would lower the deterrent value of all other US mutual defense commitments by suggesting that the US does not place a high priority on its treaty commitments.

In conclusion, the US should affirm the value of mutual defense in the prevailing mercurial security environment by remaining a staunch NATO member. At a time when ISIS and global terror rages, the Pacific is hotly contested, and the Ukraine has been invaded by an odd mixture of proxy agents and disguised soldiers, the US cannot afford to balk and abandon its NATO allies. Not only would abandoning NATO actually increase the odds of a European war by reducing deterrent, NATO allows the US to operate effectively with its allies and prove commitment to the successful doctrine of mutual defense.