Below is a list that I compiled of all the official declarations of war by the US:
18 Jun 1812 Great Britain
2/3 Mar 1815 Algiers
13 May 1846 Mexico
25 Apr 1898 Spain
6 Apr 1917 Germany
7 Dec 1917 Austria-Hungary
8 Dec 1941 Japan
11 Dec 1941 Germany
11 Dec 1941 Italy
5 Jun 1942 Bulgaria
5 Jun 1942 Hungary
5 Jun 1942 Romania
The one I’m not so sure about is the second one. I haven’t seen the text of what was passed, but from descriptions, it was more of an ultimatum than an outright declaration. Does anyone know the exact nature of what it was? And which date was it passed on?
Marshall Smelser’s book “The Democratic Republic” says that the Congressional action against Algiers in 1815 was just an authorization for the use of force and not a full scale declaration of war.
You may need to go to a big library to dig up a book on the diplomatic history of the U.S. and the Barbary States. Books on that topic tend to stay on the shelves.
Eight days after Congress ratified the Treaty of Ghent, President Madison asked them for a declaration of war against Algeria. This pirate nation had taken full advantage of the US Navy’s three year absence in the Mediterranean during its war with England, by picking off what few American merchantmen still plied those waters.
Rival commodores Decatur and Bainbridge immediately raced across the Atlantic for the honor of being the first to regain some of the honor they’d lost in the War of 1812. Decatur was the first to arrive and promptly destroyed the Algerian warship Mashouda. Bainbridge arrived in the US Navy’s first line-of-battleship, USS Independence, two weeks later just in time to witness the signing of the treaty of Algiers, whose harsh terms Decatur had dictated from behind the guns of the USS Guerriere (a small frigate).
The declaration of war was signed on March 2, 1815.
The Mashouda was demolished on June 17, 1815.
Decatur’s terms were accepted on June 30, 1815.
I’m not sure when the Treaty of Algiers was ratified. Because communication was so slow back then, probably not until sometime in late Summer or early Fall.
The website below says the treaty was approved by the Senate on December 26, 1815. There then was a dispute about whether or not the treaty was ever accepted in Algiers.
I’ve found the Journal of the House for 23 Feb 1815 on the Library of Congress site. The link to the site just doesn’t want to work, so I reproduce the text here. You can search for related Congressional documents here. I did a match-all-words search for “journal” “Algiers”, and “1815” and found about 40 documents.
On the 28th, the House passed a bill titled “An act for the protection of the commerce of the United States against the Algerine cruizers.” On Mar. 2, the House was informed that the Senate passed the bill without amendment. On Mar. 3, the House was informed that the President had signed the bill into law.