For the purpose of this poll, the question is, at the time the US entered into war, was it justifiable to do so, both in its time and in hindsight.
You only listed a small percentaghe of America's war to select from.
Here's my list of justifiable wars America fought.
1798-1800 -- Undeclared Naval War with France. This contest included land actions, such as that in the Dominican Republic, city of Puerto Plata, where marines captured a French privateer under the guns of the forts.
1801-05 -- Tripoli. The First Barbary War included the USS George Washington and USS Philadelphia affairs and the Eaton expedition, during which a few marines landed with United States Agent William Eaton to raise a force against Tripoli in an effort to free the crew of the Philadelphia. Tripoli declared war but not the United States.
1812 -- Amelia Island and other - parts of east Florida, then under Spain. Temporary possession was authorized by President Madison and by Congress, to prevent occupation by any other power; but possession was obtained by Gen. George Matthews in so irregular a manner that his measures were disavowed by the President.
1812-15 -- War of 1812. On June 18, 1812, the United States declared war between the United States and the United Kingdom of Great Britain and Ireland. Among the issues leading to the war were British interception of neutral ships and blockades of the United States during British hostilities with France.
1813-14 -- Marguesas Islands. U.S. forces built a fort on the island of Nukahiva to protect three prize ships which had been captured from the British.
1814-25 -- Caribbean. Engagements between pirates and American ships or squadrons took place repeatedly especially ashore and offshore about Cuba, Puerto Rico, Santo Domingo, and Yucatan. Three thousand pirate attacks on merchantmen were reported between 1815 and 1823. In 1822 Commodore James Biddle employed a squadron of two frigates, four sloops of war, two brigs, four schooners, and two gunboats in the West Indies.
1815 -- Algiers. The second Barbary War was declared by the opponents but not by the United States. Congress authorized an expedition. A large fleet under Decatur attacked Algiers and obtained indemnities.
1820-23 -- Africa. Naval units raided the slave traffic pursuant to the 1819 act of Congress.
1822 -- Cuba. United States naval forces suppressing piracy landed on the northwest coast of Cuba and burned a pirate station.
1823 -- Cuba. Brief landings in pursuit of pirates occurred April 8 near Escondido; April 16 near Cayo Blanco; July 11 at Siquapa Bay; July 21 at Cape Cruz; and October 23 at Camrioca.
1824 -- Cuba. In October the USS Porpoise landed bluejackets near Matanzas in pursuit of pirates. This was during the cruise authorized in 1822.
1824 -- Puerto Rico (Spanish territory). Commodore David Porter with a landing party attacked the town of Fajardo which had sheltered pirates and insulted American naval officers. He landed with 200 men in November and forced an apology. Commodore Porter was later court-martialed for overstepping his powers.
1825 -- Cuba. In March cooperating American and British forces landed at Sagua La Grande to capture pirates.
1827 -- Greece. In October and November landing parties hunted pirates on the islands of Argenteire, Miconi, and Androse.
1831-32 -- Falkland Islands. Captain Duncan of the USS Lexington investigated the capture of three American sealing vessels and sought to protect American interests.
1832 -- Sumatra - February 6 to 9. A naval force landed and stormed a fort to punish natives of the town of Quallah Battoo for plundering the American ship Friendship.
1841 -- Drummond Island, Kingsmill Group. A naval party landed to avenge the murder of a seaman by the natives.
1841 -- Samoa - February 24. A naval party landed and burned towns after the murder of an American seaman on Upolu Island.
1843 -- Africa -- November 29 to December 16. Four United States vessels demonstrated and landed various parties (one of 200 marines and sailors) to discourage piracy and the slave trade along the Ivory coast, and to punish attacks by the natives on American seamen and shipping.
1846-48 -- Mexican War. On May 13,1846, the United States recognized the existence of a state of war with Mexico. After the annexation of Texas in 1845, the United States and Mexico failed to resolve a boundary dispute and President Polk said that it was necessary to deploy forces in Mexico to meet a threatened invasion.
1849 -- Smyrna. In July a naval force gained release of an American seized by Austrian officials.
1851 -- Turkey. After a massacre of foreigners (including Americans) at Jaffa in January, a demonstration by the Mediterranean Squadron was ordered along the Turkish (Levant) coast.
1851 -- Johanns Island (east of Africa) -- August. Forces from the U.S. sloop of war Dale exacted redress for the unlawful imprisonment of the captain of an American whaling brig.
1854 -- Nicaragua -- July 9 to 15. Naval forces bombarded and burned San Juan del Norte (Greytown) to avenge an insult to the American Minister to Nicaragua.
1855 -- China -- May 19 to 21. U.S. forces protected American interests in Shanghai and, from August 3 to 5 fought pirates near Hong Kong.
1855 -- Fiji Islands -- September 12 to November 4. An American naval force landed to seek reparations for depredations on American residents and seamen.
1858 -- Fiji Islands -- October 6 to 16. A marine expedition chastised natives for the murder of two American citizens at Waya.
1858-59 -- Turkey. The Secretary of State requested a display of naval force along the Levant after a massacre of Americans at Jaffa and mistreatment elsewhere "to remind the authorities (of Turkey) of the power of the United States."
1859 -- Mexico. Two hundred United States soldiers crossed the Rio Grande in pursuit of the Mexican bandit Cortina.
1866 -- Mexico. To protect American residents, General Sedgwick and 100 men in November obtained surrender of Matamoras. After 3 days he was ordered by U.S. Government to withdraw. His act was repudiated by the President.
1866 -- China. From June 20 to July 7, U.S. forces punished an assault on the American consul at Newchwang.
1871 -- Korea -- June 10 to 12. A U.S. naval force attacked and captured five forts to punish natives for depredations on Americans, particularly for murdering the crew of the General Sherman and burning the schooner, and for later firing on other American small boats taking soundings up the Salee River.
1873 -- Mexico. United States troops crossed the Mexican border repeatedly in pursuit of cattle and other thieves. There were some reciprocal pursuits by Mexican troops into border territory. Mexico protested frequently. Notable cases were at Remolina in May 1873 and at Las Cuevas in 1875. Washington orders often supported these excursions. Agreements between Mexico and the United States, the first in 1882, finally legitimized such raids. They continued intermittently, with minor disputes, until 1896.
1874 -- Hawaiian Islands -- February 12 to 20. Detachments from American vessels were landed to preserve order and protect American lives and interests during the coronation of a new king.
1876 -- Mexico -- May 18. An American force was landed to police the town of Matamoras temporarily while it was without other government.
1899--1901 -- Philippine Islands. U.S. forces protected American interests following the war with Spain and conquered the islands by defeating the Filipinos in their war for independence.
1900 -- China -- May 24 to September 28. American troops participated in operations to protect foreign lives during the Boxer rising, particularly at Peking. For many years after this experience a permanent legation guard was maintained in Peking, and was strengthened at times as trouble threatened.
1904 -- Tangier, Morocco. "We want either Perdicaris alive or Raisula dead." A squadron demonstrated to force release of a kidnapped American.
