A White House statement described their conversation as "extremely cordial." Most importantly for Xi, Trump affirmed US commitment to the "One China" policy.
This phone call, together with a personal letter from Trump to Xi two days earlier
, which expressed US interests in seeking "constructive relations" with China, removed many of the uncertainties generated by Trump's earlier comments that the "One China" principle was negotiable.
to the "One China" principle and his threat during the election to slam 45% import duty on Chinese goods
had caused widespread concerns that the two countries were on a collision course.
One plausible explanation of Trump's apparent return to the "One China" principle could be his rising setbacks on the domestic front.
When Trump threatened to link the "One China" principle with Chinese concessions in a number of issue areas, he was rolling with a sense of invincibility after the election.
Foreign leaders were falling over each other to court him. At home and abroad, Trump looked mighty.
However, after assuming the office, Trump has encountered massive domestic frustrations.
His multiple new policy initiatives have run into fierce criticism and opposition by the public, media, and other branches of the government.
According to a poll by CNN
/ORC, a majority, 53%, disapprove of the way Trump handles his job, marking the highest disapproval for a new elected president since polls began to track these results.
The result has been that Trump has become increasingly frustrated and vexed by domestic challenges.
The last thing Trump needs is a major fight with China, which would promise to be very nasty with uncertain outcomes.
It is therefore highly likely that Trump opted to return to the "One China" principle after a rethinking about the relative priorities of the domestic and foreign policy agendas of his administration.
China courts the Trumps
Trump's return to the "One China" principle may also be an outcome of China's successful diplomatic efforts, through both conventional and unconventional tactics.
In public, China has been firm in sending out a consistent message to Trump
that the "One China" principle involved its fundamental core interests and it will to take a stand and fight to the end.
It has simultaneously pursued unconventional, backdoor approaches to shape his China policy.
Beijing is keenly aware that Trump relies closely on a very small group of advisers to guide him on policy issues, including his son-in-law Jared Kushner and daughter Ivanka Trump.
As such, China has tried to directly influence the first family to smooth relations with Trump. In fact, soon after Trump's election, Kushner attended a dinner hosted by Chinese business tycoon Wu Xiaohui,
who presides over Anbang Insurance Group that has an asset of US$285 billion and close ties to the ruling elite of China.
Then on February 1, Trump's daughter Ivanka paid a surprise visit to China's embassy in Washington to attend a Chinese New Year reception
Behind closed doors, China may have succeeded in proactively shaping Trump's position on the "One China" policy through both deterrence and accommodation.
While Trump's stated commitment to the "One China" principle has at least removed a short-term obstacle to Sino-US relations, the future of the bilateral relationship remains challenged.
Multiple issues, ranging from trade, the South China Sea or North Korea's nuclear challenge, may still lead both countries down the path to conflict.
The US and China can do a number of things to minimize conflicts and maximize cooperation.
While the US should refrain from using the "One China" principle to pressure Beijing on the trade front, the latter must consider serious concessions.
The Trump administration does have a legitimate complaint given the massive trade deficit on the US side.
China thus needs to address the "fair trade" issue. Likely concessions include greater access by US firms to the Chinese market.
On the South China Sea
issue, the Trump administration's recent statements have been encouraging.
Secretary of Defense James Mattis, during on a recent trip to Japan, expressed that there is no need for the US military
to "take drastic" moves in the South China Sea.
Moreover, he said that the US would primarily rely on diplomacy to resolve the South China Sea disputes.
China must not read this as a sign of weakness. Instead, China should refrain from further actions that may escalate the South China Sea conflict with the United States.
Finally, China should make more sincere efforts in containing the nuclear ambitions of North Korea.
Greater efforts by Beijing will not only contribute to regional stability but also strengthen Sino-US cooperation on the issue.
Such efforts can convince the Trump administration that China is indeed doing its best to help the United States with this thorny security issue.