The United States has its hands full. Washington supplies roughly half of Ukraine’s military aid while also playing the leadership role for the North Atlantic Treaty Organization (NATO) allies. The U.S. Navy is in the lead in the Red Sea, where it is fending off multiple Houthi missile and drone attacks against commercial ships. U.S. bases still operating in Iraq and Syria have to withstand repeated attacks by Iran-supported militias. Three American servicemembers have just been killed at a remote base in Jordan. The Gaza fighting could expand across the region at any time, drawing the United States into a full-blown Middle East conflict. Iran and the United States now eye each other warily. 

On the other side of the world, the Indo-Pacific Command and Pacific Fleet (IPCPF) watch Chinese warships threaten the Philippines, a U.S. treaty ally, over the Second Thomas Shoal. Just north is Taiwan, where many experts believe China could attack at any time, with President Biden repeatedly pledging full military support to the country. The Korean Peninsula remains insecure, with recent reports expressing worries that North Korea may be entertaining serious notions of starting another war. West Africa is experiencing a severe rise in Islamic insurgency, engaging U.S. special operations capabilities. Even South America has gotten into the act, where the U.S. Southern Command cannot discount the possibility that Venezuela might invade Guyana.

In addition to these challenges, the Pentagon must also deal with a technological revolution, with drones and precision strike missiles transforming the battlefield. As the Jordan and Red Sea attacks show, no U.S. operating base can now be considered immune from the reach of such weapons systems. Without a navy or a single warship, a rag-tag group of Islamic insurgents can asymmetrically threaten commerce in a strategic maritime chokepoint, launching potshots from land. While the U.S. Navy can counter the threat, it cannot decisively eradicate this kind of guerilla warfare on the high seas—a military reality that would have been inconceivable just a few years ago. The strategic enormity of these revolutionary changes has been further underscored by Ukraine’s success in driving a powerful Russian navy back from the Ukrainian Black Sea coast by using an array of land-based drones and missiles. In the future, the exercise of conventional military power can be defined less by the number of sophisticated surface ships and manned air platforms a country can develop and more by the ability to target and destroy targets using missiles and drones. If the United States goes to war over Taiwan, it will have to take on not only a larger Chinese navy but also its formidable land-based missile systems.

For almost seventy-five years, since the end of World War II, the United States military has been the backbone of the global liberal order. Its mastery and domination of military technology, combined with the productive capabilities of the American economy, has been the cornerstone of the Western alliance system. That strategic paradigm is starting to falter as relatively inexpensive yet sophisticated drones and missiles proliferate worldwide. In World War II, the United States performed the role of what Arthur Herman has called “freedom’s forge,” effectively supplying the bulk of weapons used by the Allied powers to defeat the Axis Powers. Today, the United States is straining just to supply 155-millimeter artillery shells for both Ukraine and Israel.

Even if the U.S. military-industrial base ramped up again to total conventional war production capacity, it would simply not be capable of supplying our allies at levels comparable to World War II. For example, the U.S. turned out almost 9000 warships between 1941 and 1945, over three times as many as all other countries combined. Today, U.S. Naval Intelligence estimates that China has 232 times the shipbuilding capacity of the United States. 

In the Red Sea, meanwhile, America’s European NATO allies are perfectly content to leave the Houthis to the U.S. Navy to conduct air strikes against the rebels. Yet, Western Europe is more dependent on Red Sea maritime commerce than the United States. Likewise, with Ukraine, NATO European allies have counted on the United States to meet a significant part of the burden to support Ukraine—notwithstanding that Russia’s invasion poses far more of a geographic security threat to Berlin, Paris, and Brussels than Washington. History may be dangerously repeating itself, with European democracies once again underfunding their military responsibilities, just as they did after World War I, setting the stage for Hitler and, eventually, World War II. 

As of July 2024, only eleven of thirty NATO members with armed forces have met the goal of spending 2 percent of GDP on their defense. The United States spends 3.49 percent of its GDP on defense, a level exceeded only by one ally, Poland (3.9 percent). The problem is the same in the Pacific. Taiwan, a country supposedly threatened by imminent invasion, appears content to spend only 2.6 percent of its GDP on defense. As of 2022, Japan only spent 1.08 percent. The reality is that Western democracies can and should be investing as much as the United States or even more of their GDP for defense. Given all the immediate threats in Europe, European NATO members must become the leading conventional military power in their own backyard.

Without greater military commitment from allies, the United States will not have the resources to continue facing multiple global threats. The era when U.S. military power was so dominant as to allow allies to play a secondary role has ended. If Western democracies continue to shy away from real collective defense, global instability will only worsen as the United States attempts and debates whether to shoulder a disproportionate part of the load. A significant challenge for the American national security establishment is to accept these realities and to adjust, not attacking demands for more allied support as veiled isolationism. To protect the liberal global order in a growing multipolar environment, proper collective military defense among Western democracies must evolve by a broader magnitude.

Ramon Marks is a retired New York international lawyer who writes regularly on national security issues.

Image: Shutterstock.com.