The European system of spheres of influence in China threatened US interests by:
- Limiting the US's access to the Chinese market.
- Giving European countries a monopoly on trade with China.
- Increasing the likelihood of conflict between European countries and China, which could have drawn the United States into war.
The US responded to the European system of spheres of influence in China by:
- Issuing the Open Door Policy, which called for equal trading rights for all countries in China.
- Supporting the Chinese Boxer Rebellion against the European powers.
- Sending troops to China to protect American interests during the Boxer Rebellion.