Gen. Charles Q. Brown Jr. is the U.S. Air Force chief of staff.

Like many senior officers who entered the military in the 1980s, I have lived through dramatic changes in warfighting focus in support of U.S. national security.

At the beginning of my career, I was a fighter pilot focused on the deterrence and, if necessary, defeat of the Soviet military machine. Within a few years, the Berlin Wall had collapsed, the Cold War had ended and the United States had shifted its emphasis to the Middle East and desert warfare with Iraq. Then came Bosnia, Kosovo and, finally, 9/11 and a 20-year effort to counter terrorist organizations.

We kept our nation safe, but it came at a cost.

When the Berlin Wall fell in 1989, the United States was no longer driven by the pressure of strategic competition with the Soviet Union, and we became the world’s lone superpower. In that role, we faced an unrelenting series of challenges after 9/11, while China and Russia upgraded their militaries in menacing ways — building new technologies in space, in cyberspace, on land, at sea and in the air. Now, as my service’s senior uniformed officer, I have evaluated the Air Force’s need to rapidly pivot to address these security challenges — and published a strategic approach whose title embodies our imperative: “Accelerate Change or Lose.”

It’s not hyperbole. We know from detailed war games played out over the past decade that winning any conflict with China or Russia would require marshaling significant new resources. Both strategic competitors have built formidable and advanced defensive systems, are bolstering offensive and defensive capabilities in space and are rapidly developing the next generation of technologies in autonomously operated weapons, precision missiles, artificial intelligence and hypersonic flight.

In many ways, this moment is reminiscent of the interwar years of the 1930s, when the horrors of trench warfare from World War I led to innovations such as long-range strategic bombing, carrier aviation and highly maneuverable ground forces. Although some of these emerging concepts were still experimental prior to World War II, we made enough progress so that when the shock of Pearl Harbor and early victories won by the Germans and Japanese were overcome, we were able to successfully prosecute the war with weapons and tactics that had been battle-tested in peacetime drills.

Today, given the lethality and accuracy of modern armaments, the Air Force might not have such a cushion if we again have to fight a major conflict alongside our sister services, allies and partners. To ensure success — or head off failure — we must rapidly develop and deliver new capabilities. We must make difficult but necessary choices to retire less relevant capabilities that we know won’t contribute to deterring or won’t survive in the next big fight.

And we must change culture: We must sharpen our focus on the “pacing threat” — that is, the leading danger to our security — and acquire a strong sense of urgency that pervades everything we do. Preparing our airmen to understand what it means to compete against China, our pacing challenge, is now an Air Force imperative and the culture change we seek.

I had the privilege to serve as the U.S. Central Command’s air component commander during the Defeat ISIS campaign that began in 2014. I know that our way of operations was being studied by both China and Russia. Three years ago, I took command of Pacific Air Forces in Hawaii, about as far removed from counterinsurgency warfare as possible. While focusing on the problem at hand — fighting the Islamic State — I did my best to stay abreast of global trends. But little could have prepared me for what I have learned since then about the comprehensive advancement in fielded capability, technology and tactics that marked the rise of the Chinese armed forces in the Indo-Pacific region.

The Air Force has mapped out a path to compete, deter and win in this new strategic environment, and we’re moving swiftly to implement change. It will involve rigorous analysis of the problem, difficult choices and close collaboration with Congress, industry and academia. To do this, we are removing bureaucratic hurdles, emphasizing a culture of competition and creating processes that will bring rapid digital design concepts to fruition, aiming to bring new technologies online at the pace that strategic competition demands.

My passion for sounding the alarm and trumpeting the need for rapid and innovative change is born of experience. We can be ready. But we must act with deliberate speed and a clarity of purpose not seen in a long time.