ABOUT THE AUTHOR: Mike Pence served as the 48th vice president of the United States and is the founder of Advancing American Freedom.

While America remains the leader of the free world and the arsenal of democracy, the international framework of free nations built after World War II is under its greatest strain in generations.

Russia is waging a brutal war of conquest in Europe, shattering borders by force and daring the West to respond. China is intensifying its military pressure on Taiwan, conducting large-scale exercises that simulate encirclement and invasion. Iran, weakened but still deadly like a wounded predator, is threatening to exact revenge on America and Israel. The United States must meet these challenges with strength and resolve.

President Donald Trump’s proposal to raise America’s defense budget to $1.5 trillion is an absolute necessity in a world that has grown more violent and more dangerous in recent years. At a moment when authoritarian regimes are probing for weakness, the United States must ensure that its armed forces remain unquestionably capable of deterring aggression — and, if deterrence fails, of winning decisively.

The greatest threat to American security and prosperity is Communist China, a near-peer competitor with global ambitions and the industrial capacity to pursue them. Nowhere is China’s military power clearer than at sea. China has assembled the largest navy in the world by number of vessels, and its shipbuilding capacity is 200 times greater than our own. In a single year, Chinese shipyards launched an aircraft carrier and dozens of additional warships — destroyers, cruisers and submarines — at a pace the United States cannot currently match. In a long competition between industrial systems, time favors the side that can build faster. Today, that is undoubtedly China.

Against this backdrop, incrementalism is a luxury we can no longer afford. While the most recent National Defense Authorization Act authorizes spending near historic highs, it still amounts to just 3% of our gross domestic product. That is well below the 5% benchmark we urge our NATO allies to meet — and well below what the moment demands. A $1.5 trillion defense budget would finally align American capabilities with American responsibilities, and truly restore the military superiority that has kept the peace for decades.

Consider shipbuilding alone. The NDAA authorizes $26 billion for naval construction — a figure that sounds impressive until one recalls that a single Ford-class aircraft carrier costs roughly half that amount. Deterrence against a maritime power like China requires us to scale quickly and sustain our investment. We cannot rebuild a navy capable of defending the Indo-Pacific with modest and sporadic budget increases every few years.

Critics will warn of costs. But America’s long-term debt crisis is not driven by defense spending. It is driven by unchecked entitlement growth that demands serious reform. Weakening our military will not solve that problem — but it will create new ones. National defense is not a discretionary indulgence. It is the first and most important responsibility of the federal government.

Just as important as the dollars themselves is the signal this proposal sends. A defense budget of this magnitude tells our adversaries that America is serious about defending our allies, serious about protecting our interests, and serious about winning any conflict we are forced to fight. It reassures friends who depend on American leadership and gives pause to rivals who would otherwise calculate that the balance of power is shifting in their favor.

The highest purpose of military strength is not to wage war, but to prevent war in the first place. Peace can only be preserved when strength is unmistakable and resolve is unquestioned. The men and women who wear the uniform of the United States deserve nothing less than the resources required to succeed in the most dangerous strategic environment of our lifetimes.

The question before us is not whether America can afford to lead. The question is whether we can afford not to.