The Polycene era, which we have just entered, will be the first era in human history in which humanity must govern, innovate, collaborate and coexist at a planetary scale to thrive, because all of our key challenges -- governing A.I., curbing nuclear proliferation, managing climate change and managing a world where more people than ever will be living outside their birth nations are planetary in scale. It will take everyone, everywhere, rowing together. “The decisive test of our age,” Oxford economist Eric Beinhocker remarked to me, “is whether we will recognize this in time.” We will only pass that test if America takes the lead. No other nation has (or at least had) the respect and power to do so than America. But America can only lead if we get back to our great national project of making ``out of many, one.'' We are off our project. We need to model how to create 'one' from 'many' again, especially since the 'many' is now far more diverse. We look more like the world and the world looks more like us than ever before. If we go first and model that for the world, everything is possible.