During the Crisis Era (about 200 years after the events in the first book), Earth had surpassed the Trisolarians in building a much larger and faster fleet despite the technology sanctions by the Trisolarians. The Trisolarians sent out a Droplet towards Earth, which was interpreted as a Trisolarian “gift” and a sign that the Trisolarians are about to concede defeat and seek friendship with Earth instead. The Droplet then ended up annihilating the entire Earth space fleet (the Doomsday Battle).

An apt analogy of the Droplet today is the invisible yet massive global financial institutions that serve the US - the dollar hegemony - which if utilized properly, can annihilate the world’s economy and take out the Chinese semiconductor industry (and many other things) all at once. This is also why de-dollarization is at the forefront of the “multipolar” fight today, because nobody would be able to escape from the weaponized dollar eventually.

So yeah, the US might send out a fake friendship gift soon to China only to turn out to be some deadly financial weapon.