Did the Us, Under Sieging Ping, Take Actions That Were Threatening to the Us?

Vivian, i don't know a person thats saying this is it. But if you remember, we've been in a period of engagement with china for forty odd years. And then something happened. Why would the us? Within ofin a few years, not want to support china any more and suddenly we're in this conflict? Did the us? Policy of forty odd years just change? Or where did the sieging ping take actions that were threatening to the us? Rightly? or wrongly threatening?"