The Blockade of Veracruz was a conflict during the Mexican-American War.The blockade of Veracruz was extremely important in the Mexican-American War in stopping the trade of contraband.Secretary of the Navy George Bancroft instructed Commodore Conner's Home Squadron to "exercise all the rights that belong to you as commander-in-chief of a belligerent squadron." On 14 May 1846, Conner proclaimed Veracruz, Alvarado, Tampico and Matamoros under blockade. Conner sent the sloop-of-war St.