In George Washington’s first annual address to Congress he made the famous statement, “To be prepared for war is one of the most effectual means of preserving peace.” But he offered no clues to how in modern times the United States should prepare for war. Do we wait to ramp up defense spending only when the crisis is on top of us, allowing for significant defense cuts in times like these when our nation needs to get its fiscal house in order?

That’s the view of some supporters of the $500 billion in deep sequestration cuts to national defense slated to begin in January. As history demonstrates, however, it is a false premise to assume that with the end of the war in Iraq and planned drawdown in Afghanistan, we can rationally reduce defense spending beyond $487 billion in cuts the Pentagon is already planning to absorb without affecting national security, just as we “demobilized” following previous wars. The fact is that in every conflict involving American forces since the Korean War there was no mobilization and subsequent demobilization.

Mobilization for war in the classic sense involves a major ramp up in defense spending, large segments of the citizenry exchanging their civilian clothes for military uniforms, and industry converting from making consumer goods to producing military weapons. Under this construct, when a war ends, a return to “normalcy” is characterized by defense cuts and a shrinking military.

Not since the Korean War has mobilization as defined above been put in place. During Vietnam, America fought using the existing budget process, with the forces and equipment we had on hand, expanding the size of the Army somewhat with a limited draft. The president did not even call the reserves to duty. After the fall of Saigon, resources were shifted to provide depleted and demoralized forces with new and modern equipment. That process took more and more money, culminating with a large military build-up during the late 1970s and 1980s, which allowed the United States to conduct successfully the first Gulf War against Saddam Hussein.

As was the case in Vietnam, the U.S. engaged in foreign conflicts this past decade with the force structure and weapon systems bought and assembled during the previous two decades. Indeed, the vast majority of the additional defense funding since 2001 primarily covered the personnel, operations and maintenance expenses of prosecuting two conflicts in remote, undeveloped theaters, and developing and buying the equipment needed to reduce the vulnerability of our ground troops to mines and improvised explosive devices.

Although new armored vehicles designed for these threats met an urgent need in Iraq and Afghanistan, they may or may not be relevant in future conflicts. Clearly, the war on terrorism has been fought with existing military weapons and equipment, which have not been extensively replaced or upgraded despite unprecedentedly heavy usage rates. Savings in the defense budget will occur as operations in Afghanistan wind down, but savings in the defense base budget – which funds personnel, installations, and new equipment – will be harder to realize.

We know the United States faces looming threats, making it risky to reduce our military posture, presence and operational readiness. In the Middle East, Iran refuses to engage the West, as it shows no sign of giving up on its nuclear ambitions, and the Syrian civil war gets deadlier by the day. In Yemen and parts of Africa, Al Qaeda still exists, intent on attacking America. In Northeast Asia, North Korea’s recent leadership transition was followed by provocative actions that threaten the region.

Over the long term, the United States must invest in military capabilities to deny potential adversaries the ability to counter our technological advantages that allow us to see battlefields with greater clarity and accurately strike targets from greater distances. We are already witnessing some of the world’s major military powers making large strategic investments in anti-satellite weapons, cyber warfare technologies and personnel, and other weapons that would put our current technological edge at risk. These investments are a potent reminder of the importance of maintaining robust defense investment and research and development funding.

There is no doubt that our country’s fiscal challenges are real and must be addressed. But those who believe we can continue to cut defense because of a post-conflict demobilization are ignoring reality. We no longer rapidly mobilize as threats materialize. We have to prepare now for potential wars in order to preserve the peace long into the future. To bring down our force levels to those last seen after the Korean War in 1953 and not to replenish our equipment and modernize our systems based on an outdated idea of how America must gear up for war and gear down afterward is bad policy in the extreme.

Dr. Goldstein is the former Lead Writer at NASA and was also a White House aide.