The flows of traded goods across countries are known to follow a gravity pattern: Their volumes are greater between countries that are larger in size and closer to each other. We find a similar pattern in the flows of territories across countries between 1870 and 2008. During this period, countries experienced inflows and outflows of territories, mirroring the international flows of goods. We find three other pieces of critical evidence supporting that the two flows interact through similar economic motives. Our findings illustrate the usefulness of international trade models for understanding international politics.

中文翻译：

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两个引力的故事*

众所周知，国家间贸易商品的流动遵循引力模式：在规模较大且彼此接近的国家之间，贸易量较大。我们发现，1870年至2008年间，各国之间的领土流动具有类似的模式。在此期间，各国经历了领土的流入和流出，这与国际货物的流动相类似。我们发现了另外三个关键证据，证明这两种流动是通过相似的经济动机相互作用的。我们的发现说明了国际贸易模型对于理解国际政治的有用性。