The embargo was imposed in response to violations of United States neutrality, in which American merchantmen and their cargo were seized as contraband of war by the belligerent European navies. The British Royal Navy, in particular, resorted to impressment, forcing thousands of British-American seamen into service on their warships (under British law of the time, having been born British they were still subjects of the Crown). Britain and France, engaged in the Napoleonic Wars, rationalized the plunder of U.S. shipping as incidental to war and necessary for their survival. Americans saw the Chesapeake-Leopard Affair as a particularly egregious example of a British violation of American neutrality. Perceived diplomatic insults and unwarranted official orders issued in support of these actions by European powers were argued by some to be grounds for a U.S. declaration of war.