The United States next attempts to launch a massive invasion of Louisville to knock the Confederates out of Kentucky but it soon becomes a bloody stalemate. The decision of Stonewall Jackson to command the defense personally, the incompetence of U.S. commanders, and most of all, the use of breech-loading artillery and repeating rifles make taking the city very difficult. The Confederate Army refrains from any major invasion of United States territory for two reasons: first, it does not have the resources to conquer the United States, and second, the Confederacy's success hinges on the support of the United Kingdom and France, who feel they are aiding a smaller nation wrongfully attacked by a larger one, and launching offensives into the United States would be seen as an act of aggression which might cost the Confederacy foreign support. Galled by orders to wage a purely defensive war, Jackson takes them to the extreme, pioneering tactics of urban warfare and full-scale trench warfare which devastates Louisville (in scenes reminiscent of real life World War I). The Louisville campaign quickly bogs down for the United States, and results in very heavy losses with little territory gained. The United Kingdom and France continue to blockade the United States; French forces from Mexico also shell Los Angeles, while the British bombard San Francisco and raid the Federal mint there.