This seapower approach to the world became the sine qua non of early American foreign policy.

这种对世界的海权方针成为早期美国外交政策的必要条件。

There have been only a few true seapower nations in history-notably Great Britain, the Dutch Republic, Venice, and Carthage.

历史上只有少数几个国家是真正的海权国家——著名的有大不列颠（英国）、荷兰共和国、威尼斯和迦太基。

The United States began its life purposefully as a seapower: The Constitution explicitly directed Congress " to provide and maintain a Navy."

美国一开始就有目的地成为一个海上强国: 《宪法》明确指示国会“配备并维持一支海军”。