Throughout the U.S. presidential campaign, there was a confident assumption that Donald Trump would "pivot" and begin to act like a more conventional candidate. That never happened. After his surprise election win, it has been asserted just as certainly that the demands of the Oval Office would force him to act more presidential. The world is still waiting. For some, Trump's disregard for precedent and protocol is refreshing and amusing; for many others, his actions are troubling and dangerous, with the potential to upend assumptions upon which rest regional peace and stability.

The most recent example of "unpresidential behavior" was the phone call that Trump took from Taiwan President Tsai Ing-wen last week. The call was the typical congratulatory message that one head of state offers to another, with best wishes and hopes for a productive future relationship. The problem is that Taiwan is not, except to a handful of governments around the world, "a state." It is, according to the "one China" policy that Beijing has demanded countries honor if they want to have relations with China, a "renegade province" that is slated to reunite with the mainland. In that light, Trump's chat, however banal or benign, was a stunning breach of diplomatic protocol.

It is not clear, however, if it is anything else. Reports from the Trump camp indicate that it was a deliberate gesture, arranged ahead of time by individuals either in or associated with the Trump transition team, and is intended to signal a new era in the United States' relationship with China and that long-established certainties are up for reconsideration.