Final answer:
The ideological differences between the United States and the Soviet Union, rooted in their contrasting political and economic systems, caused friction and led to the outbreak of the Cold War.
Step-by-step explanation:
The ideological differences between the United States and the Soviet Union that caused friction and led to the outbreak of the Cold War were rooted in their contrasting political and economic systems. The United States believed in capitalism and democracy, promoting individual freedoms, private property, and free-market competition. In contrast, the Soviet Union embraced communism, enforcing a centralized, state-controlled economy and suppressing individual liberties. These clashing ideologies and their respective ambitions for global supremacy created a deep divide between the two nations, fueling a series of conflicts and proxy wars throughout the Cold War era.