U.S. President-elect Donald Trump ran an election campaign that challenged American diplomacy's long-standing principles and shibboleths. Since his election triumph, Trump is rewriting the rules of presidency and signaling that his foreign policy approach will be unconventional.

Even before assuming office, Trump has moved away from U.S. President Barack Obama's foreign policy approach by staking out starkly different positions on several sensitive subjects, including China, Taiwan, Israel, terrorism and nuclear weapons. A Trump presidency may not bring seismic shifts in American policy but it is likely to lead to significant change in U.S. priorities, geopolitical focus and goals as well as in the tools Washington would be willing to employ to help achieve the desired objectives.

No country faces a bigger challenge from Trump's ascension to power than China, which has been flexing its military and economic muscles more strongly than ever. After relishing the Obama administration's unremitting obsequiousness toward it, Beijing must now brace up and face an assertive new national security and economic team in Washington that is unlikely to put up with its covert territorial expansion and trade manipulation.