The telephone exchange between the two breaks a long-standing tradition that had governed US-Taiwan relations for many decades and raised legitimate speculation about its implications for the future of China-US and Taiwan-US relations.
This phone call may not necessarily imply significant changes in the above relations under a Trump presidency.
According to Trump's Twitter message, it was Tsai who initiated the phone call. In fact, his message highlighted the fact by capitalizing Tsai "CALLED ME" to offer her congratulations.
Trump could be signaling to the world that people should not read too much into this telephone call. The audience of his message could include Beijing.
Based on the initial reaction by Chinese Foreign Minister Wang Yi, it seems that Beijing has opted for a low-key response. Wang instead criticized Taiwan for playing "dirty tricks" to manipulate Taipei-Washington relations.
No diplomatic savvy
Nonetheless, this phone call may offer important clues about how Trump may handle foreign policy decisions.
It seems to vindicate the widespread expectations that he will not be able to handle sensitive issues with diplomatic savvy.
Instead, his impulse may cause unintended consequences and raise eyebrows in foreign capitals. In fact, this episode with Taiwan's leader mimicked his phone call with Pakistan's Prime Minister Nawaz Sharif
on Wednesday. Trump's very warm words toward Sharif and Pakistan have caused resentment in many circles of India.
Both cases imply that the world may need to get used to a less disciplined US president who is not bounded, or doesn't want to be bounded, by traditional diplomatic rules and norms that would have constrained another US president.
Indeed, less than one hour after his initial Twitter message, Trump sent another message showing his objection to the established rules and norms: "Interesting how the US sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call."
The conclusion here is that Trump's phone call with Tsai Ing-wen may not foretell major shifts in US relations with China and Taiwan.
It was more likely a reflection of Trump's personality and suggests that his presidency may be fraught with unintended diplomatic consequences triggered by his impulsive actions and words.
New Cold War
This scenario does not bode well for US-China relations, which have seen rising tension in the recent years.
Indeed, lack of strategic mistrust between them is driving their relationship in the direction of a new Cold War.
In this context, the worst thing that may happen involve actions or words by either party that further amplify their mutual strategic mistrust.
Trump therefore needs to learn to become a more disciplined and diplomatic savvy president when it comes to the highly sensitive trilateral relations between Beijing, Taipei and Washington.
The Taiwan Strait remains one of the most dangerous flashpoints in East Asia.
The return to power earlier this year by the Democratic Progressive Party
, which traditionally favors independence for the island, has rekindled the prospect of instability across the Taiwan Strait.
Indeed, Tsai Ing-wen has skirted around the "1992 consensus"
-- a tacit understanding reached between the Chinese Communist Party and Taiwan's then-ruling Kuomintang leadership that there was "one China," although either side was free to interpret what that meant.
The revisionist inclination of a DPP government poses threat to the stability of both Beijing-Taipei relations and Beijing Washington relations.
In this context, the Trump administration should avoid sending the wrong signals to Tsai's government as that would only embolden her to pursue more revisionist policies, which will in turn heighten the prospect of direct military conflict between China and the United States.
War in the western Pacific is the last thing that Beijing and Washington wants to see.
It is therefore in the interest of the United States to continue to restrain Taiwan's revisionist tendency while simultaneously deterring Beijing from unilaterally changing the status quo by force.