During the Civil War, Union forces established a blockade of Confederate ports designed to prevent the export of cotton and the smuggling of war materiel into the Confederacy. The blockade, although somewhat porous, was an important economic policy that successfully prevented Confederate access to weapons that the industrialized North could produce for itself. The U.S. Government successfully convinced foreign governments to view the blockade as a legitimate tool of war.
...The blockade had a negative impact on the economies of other countries.
...Confederate leaders were confident that Southern economic power would compel European powers to intervene in the Civil War on behalf of the Confederacy, Britain and France remained neutral despite their economic problems,
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The Blockade of Confederate Ports, 1861–1865
During the Civil War, Union forces established a blockade of Confederate ports designed to prevent the export of cotton and the smuggling of war materiel into the Confederacy. The blockade, although somewhat porous, was an important economic policy that successfully prevented Confederate access to weapons that the industrialized North could produce for itself. The U.S. Government successfully convinced foreign governments to view the blockade as a legitimate tool of war.
...The blockade had a negative impact on the economies of other countries. ...Confederate leaders were confident that Southern economic power would compel European powers to intervene in the Civil War on behalf of the Confederacy, Britain and France remained neutral despite their economic problems,
https://history.state.gov/milestones/1861-1865/blockade