[4] He was a strong proponent of the Open Door Policy (a system of equal trade and investment and to guarantee the territorial integrity of Qing China) and a critic of imperialism.

Reinsch criticizes national imperialism on the basis of its threat to world peace, the subjugation of indigenous peoples and its diversion of focus from domestic reform.

However, Reinsch was in favor of expansionism on the grounds of a "white man's burden,"[1] although he expressed skepticism that even well-intentioned colonial activities would have its intended effects.

[10] He writes,Experience seems to show that even those institutions which are by us considered the very foundation of good government may have harmful results when introduced into another society.

[10]According to Ido Oren, "Reinsch wrote so extensively on the subject matter in which he was implicated as a diplomat and adviser—international diplomacy, international organization, and imperialism—that it becomes nearly impossible to draw a neat line separating scholarship from politics in his career.

[12] In 1913, President Woodrow Wilson appointed Reinsch United States Minister to China, a position he held until 1919[6][13] when he became legal advisor to the Chinese government.