This is the first in-depth study to address the financing of the American-Mexican War of 1846-48. Floating the Mexican War loans was the greatest single endeavour of the American financial community during the 1840s. Under President Polk, the Treasury issued three loans totalling $49 000 000. Investment bankers enthusiastically marketed these treasury notes and bonds directly to the international investing public. Cummings argues that the successful financing of the American-Mexican War had a long-term beneficial effect on American financial institutions and markets. At home, the stability of the Independent Treasury was assured, and abroad, America's international credit standing was restored. Most importantly, the dealing of government issue by investment bankers was a decisive step towards modern public finance.