In 1970, I traveled to Egypt as part of a delegation representing the United States at the funeral of President Gamal Abdel Nasser. Back then, Egypt was closely aligned with the Soviet Union. When we arrived in Cairo, it seemed that everywhere one looked there was evidence of the Soviet presence – Soviet tanks, missiles, and troops.

During the visit, we were scheduled to meet with Anwar Sadat. No one in our delegation was sure what to expect, given the uneasy relations between our two countries at the time. To our surprise, Sadat told us that he, in fact, had respect for the US. The reason? As a young military officer, he had visited our country and had had an excellent experience.

And, indeed, within two years of taking power, Sadat expelled the Soviets from Egypt and began to build a friendship with the US that, despite challenges and periodic differences, has proven important and valuable ever since.

I mention the importance of these military-to-military relationships because the US in this new century is undergoing a significant transformation of its military arrangements and partnerships around the globe – necessary adjustments based on the new realities, and new threats, that have emerged since the end of the Cold War.

It is important to note that since 2001, the US has probably done more things, with more nations, in more constructive ways, and in more parts of the world, than at any other time in its history.

In the wake of the September 11, 2001, terrorist attacks, President George W. Bush helped fashion and lead the largest coalition in history – 80-plus nations – to fight the global war on terror. Furthermore, roughly 60 nations are currently cooperating in the Proliferation Security Initiative to prevent dangerous weapons and materials from being transported to terrorists or outlaw regimes.

There has been a rethinking of the structure and role of our traditional military alliances, including the North Atlantic Treaty Organization, which is setting up a new NATO Response Force and has moved outside Europe for the first time with the International Security Assistance Force in Afghanistan.

The focus of attention today is on Iraq and Afghanistan. But in future decades, priorities will change. And much of what we may be called on to do in the future will likely be determined by choices made by others.

Consider Russia, a nation with vast natural resources, an educated population, and a rich heritage of scientific and cultural achievements. Like Americans and others around the world, they are threatened by violent extremism. Russia is a partner with the US on some security issues, and our overall relationship is the best it has been in decades. But in other ways Russia has been unhelpful – using energy resources as a political weapon, for example, and in their resistance to positive political changes in neighboring countries.

The same holds true for China. The Chinese people are educated and talented, and their country has great potential, with high economic growth rates and an industrious work force. Nonetheless, some aspects of Chinese behavior remain unsettling and complicate our relationship. Last year, a US Department of Defense report noted that China’s defense expenditures appear to be much higher than acknowledged by the Chinese government. Coupled with a notable lack of transparency, this understandably concerns China’s neighbors.

In addition to the choices that these and other countries make, America’s own choices will be an important factor determining what kind of future it faces. From time to time, US public sentiment has opposed playing an active role in the world and fulfilling our commitments to allies – and, indeed, to the cause of freedom. In the early 1970’s, as US ambassador to NATO, I remember having to fly back from Europe to testify against legislation in our Congress that would have pulled US troops out of Western Europe and NATO, just as the Soviet Union was in the midst of a huge military buildup.

Today, nations that were members of the Soviet Union’s Warsaw Pact, as well as some of the former Soviet Republics – countries that we used to call “captive nations” – are valued members of NATO and represent some of our most stalwart allies in the War on Terror.

This did not happen by accident or by chance. Looking forward, I am convinced that if we have the wisdom, courage, and strength to adjust long-standing strategic arrangements, embrace new partners, and, above all, persevere in the face of adversity and difficulty, we will see a similar victory in this “long war” against violence extremism and the other threats that may emerge in an uncertain new century.