Belmont also used his influence with European business and political leaders to support the Union cause in the American civil war , stopping the Rothschilds and other bankers from lending to the Confederacy and meeting personally with the British prime minister , Lord Palmerston , and members of Napoleon IIIâ s government . Belmont also used his influence with European business and political leaders to support the Union cause in the American civil war , dissuading the Rothschilds and other bankers from lending to the Confederacy and meeting personally with the British prime minister , Lord Palmerston , and members of Napoleon IIIâ s French government .