Climate, competition, defense—these evolutionary saws and scissors can explain much of the diversity of leaves. Yet if you pick up two leaves in your backyard, most of what differs between them—the details naturalists have spent thousands of years naming—remains unaccounted for. Evolution can whittle similar forms again and again when confronted with similar circumstances. But through innovation and chance, evolution can also work in the abstract: Jackson Pollock dashing paint on the canvas of life. We should not expect to understand every tomentose blade or arachnoid lobe. Sometimes it is enough to step back and know a masterwork when we see one, whether it hangs in a museum or from its petiole on the branch of a park tree. Not that leaves care whether you notice; the blessing they convey comes each day with the rise of the edible sun.
We all know that fears and misperceptions linger on both sides of the Pacific. Some in our country see China’s progress as a threat to the United States; some in China worry that America seeks to constrain China’s growth. We reject both those views. The fact is that a thriving America is good for China and a thriving China is good for America. We both have much more to gain from cooperation than from conflict. But you cannot build a relationship on aspirations alone. It is up to both of us to more consistently translate positive words into effective cooperation — and, crucially, to meet our respective global responsibilities and obligations. These are the things that will determine whether our relationship delivers on its potential in the years to come. We also have to be honest about our differences. We will address them firmly and decisively as we pursue the urgent work we have to do together. And we have to avoid unrealistic expectations.
It is important to emphasize that my focus is not on how China will behave in the immediate future, but instead on how it will act in the longer term, when it will be far more powerful than it is today. The fact is that present-day China does not possess significant military power; its military forces are inferior to those of the United States. Beijing would be making a huge mistake to pick a fight with the . military nowadays. Contemporary China, in other words, is constrained by the global balance of power, which is clearly stacked in America’s favor. Among other advantages, the United States has many consequential allies around the world, while China has virtually none. But we are not concerned with that situation here. Instead, the focus is on a future world in which the balance of power has shifted sharply against the United States, where China controls much more relative power than it does today, and where China is in roughly the same economic and military league as the United States. In essence, we are talking about a world in which China is much less constrained than it is today.