What is Diplomatic Power?

The ability for a state to influence another state through the use of diplomatic instruments such as trade embargos, treaties and the use of veto powers.

Examples


Public Denouncement:
China denounced the french government in June of this year after they 'honored' the Dalai Lama, they stated that France's action would "harm Sino-French relations".
Source

Use of Veto:
China continued to block sanctions on the Sudanese government over the Darfur crisis because of ties to the country. Most security council members voted to get sanctions on Sudan however the movement couldn't be passed because of China's power of veto
Source

What are the benefits for China in using diplomatic instruments?

In using diplomatic instruments, China is able to repress separatist movements within it's borders and ultimately further it's "One China Policy" and therefore it's territorial integrity.

What are the drawback in China using diplomatic instruments?

In using diplomatic interests, China risks undermining it's 'international standing' which is a key aspect of their national interest.