United Nations Headquarters...
Or, more accurately, should it now be called the headquarters of the PDC, the Planetary Defense Council?
"..."
At that moment, in an office on the top floor of the PDC headquarters, Sai, the former UN Secretary-General and now PDC Secretary-General, was buried in paperwork, approving one document after another.
Ever since the Guzheng Project, humanity had learned more about the existence of the Trisolarans. They knew that sophons had arrived on Earth, locking down humanity's fundamental microphysics and research. They knew that the sophons were monitoring humanity on every level. And they knew that more than a thousand Trisolaran spacecraft were heading for the Solar System and were expected to arrive within a few centuries. These and other terrifying facts had come to light.
As human society began to panic, the governments of the world also became more united than ever before. Building on the framework of the old United Nations, they established the Planetary Defense Council—the PDC—to replace the UN and serve as the highest authority, uniting the nations and devising countermeasures against the Trisolaran invasion.
Without question, then, the highest authority on Earth, now under threat from the Trisolarans, was Sai, Secretary-General of the Planetary Defense Council!
Of course, that highest authority was only nominal. It wasn't absolute.
Even Secretary-General Sai faced all kinds of constraints and oversight, from the newly established International Court of Humanity, for example. And even she couldn't directly command or deploy the space forces of individual nations or continents.
After all, the PDC was ultimately just an organization, much like the old United Nations, that brought the nations of the world together to pool their resources, manpower, and materiel to resist the Trisolarans. It was a new UN with far greater powers than the old one, which had been