本文重點在分析2000-13的美國對華政策，但也就上世紀國際權力架構與分配，國際大局的演變，和主政政黨與領導人的異動如何影響美國的亞太和中國政策加以研析。美國是亦民主國家，重視推動人權和民主化，外交在某種程度也是「內政的延長」，受到國會，企業界學界和民間輿論的影響，這些都是需要納入考慮的變數。 1949年共產黨在中國奪權後，美中雙方缺少互信，有競爭也有對抗。基本上，美國對華政策必須因應國際社會的變化，尤其是中國崛起及其稱霸的意圖及政策。歐巴馬政府從2010年後執行「重返亞太」策略但多次強調不是針對中國，但北京確認為此一策略是對付中國，要圍堵和弱化中國。解放軍多年來發展和部署「反介入」與「區域拒止」戰力對抗和遏止美國重返亞太。 美國如何評估中國的威脅及聯合友邦抗拒中國霸權主義行徑，以維護國家利益，國際和平和盟友的安全？未來，習近平和其他中國領導人，包括解放軍將領，如何追求「大國夢」和「新型大國關係」，與美國分庭抗禮將界定美中關係和美國對華政策。近年解放軍主導對美國大規模的網路攻擊，滲透美國企業，竊取政府，國防和商業情報，美中已經以另一種形式方式開戰，即所謂「資訊或信息戰爭」。

This article seeks to explain the making of U.S. policy in the 21st century, especially during 2000-13. It also analyzes how changes in the international system and the balance of world power, as well as changes of U.S. leaders, shape American foreign policy toward China and Asia-Pacific. Whereas the economic considerations are an important policy ingredient, the article cautions against the Marxist fallacy of “economic determinism.” Likewise, moralism (e.g. concerns for human rights) or idealism alone does not dictate U.S. policy, as policy leaders are sufficiently realistic and pragmatic to take into account many other important factors. Basically, American China policy in the 21st century is a response to China’s economic and military rise. Beijing’s quest for domination and hegemony in Asia-Pacific and the South China Sea has compelled the Obama administration to forge the “Pivot to Asia” strategy. Meanwhile, Chinese new leader Xi Jinping is calling for a new type of major power relationship, namely a parity between the world’s two superpowers. In essence, Beijing is challenging the Pax Americana and intends to remake the international order in Asia-Pacific, which is to be ruled jointly by China and the U.S.