War and Expansion

The United States has expanded its borders through both war and diplomacy. The Louisiana Purchase in 1803 and the acquisition of Alaska in 1867 brought new lands and people within America’s geopolitical footprint. Since 1789, Congress has also approved 11 declarations of war and debated and passed authorizations for the use of military force. Under the terms of the Treaty of Guadalupe-Hidalgo, which ended the War with Mexico in 1848, the U.S. acquired a swath of land that composed much of the modern-day American Southwest. At the turn of the twentieth century, America’s emerging role as a global power shaped debate in the House about the country’s overseas empire.

Irv Swanson's Gavel/tiles/non-collection/4/4-20-War_gavel-2005_124_000.xml Collection of the U.S. House of Representatives, Gift of Irving Swanson
About this object
Speaker of the House Sam Rayburn of Texas presented this gavel, used during this historic session, to Reading Clerk Irv Swanson in appreciation for reading President Roosevelt’s war message and taking the roll call vote.

Historical Summaries

Jay's Treaty
On April 30, 1796, the House appropriated funds for Jay’s Treaty with Great Britain by a 51 to 48 vote. Many viewed the treaty as a contemptuous capitulation to London. The Senate approved Jay’s Treaty, angering many in the House who believed they had the option to essentially override treaties requiring appropriations packages.

The Louisiana Purchase
President Thomas Jefferson approved and signed an act to pay France $11 million dollars for the Louisiana Purchase on November 10, 1803. The House discussed and approved the payment with a 90 to 25 vote on October 25, 1803.

Power to Declare War
Like many powers articulated in the U.S. Constitution, Congress’ authority to declare war was revolutionary in its design, and a clear break from the past when a handful of European monarchs controlled the continent’s affairs.


Rising up in the House—Part I: Rep. Dyer and the Irish Rebellion of 1916
On April 24, 1916, a band of Irish republicans took up arms against the British government in what became known as the Easter Rising. The rebels proposed a vision of a unified Ireland, liberated from the economic and political restrictions imposed by the British government. The Irish insurgency and its aftermath both captivated and appalled the U.S. public—including Congress.

The Apportionment Act of 1842: “In All Cases, By District”
In a decision that shaped the makeup of the House for decades, Congress broke with 50 years of precedent to make two dramatic and substantial changes: it shrunk the size of the House for the first time in U.S. history, and standardized what we would recognize as the modern congressional district.

Primary Sources

President John F. Kennedy's 1961 Presidential Message
On May 25, 1961, President John F. Kennedy responded to urgent national needs in the areas of foreign aid, international and civil defense, and outer space brought Kennedy to address Congress for a second time in 1961.

Map of the Western Territories
On December 5, 1848, President James K. Polk transmitted his Annual Message to Congress. He used this map as an exhibit to illustrate his desired plan for the land acquired through the Treaty of Guadalupe Hidalgo that ended the Mexican-American War earlier in the year.

Constitutional Amendments, Treaties, and Major Acts of Congress
A key ingredient of all amendments, treaties, and major legislation is debate and diplomacy. The following charts from the minority representation in Congress publications showcase major acts of Congress that influenced both domestic and foreign relations.

Oral Histories

U.S. Declarations of War in 1941 Documentary
Early in the afternoon on December 8, 1941, Irving Swanson sat at the rostrum of the House and stared into a packed chamber. A few feet away, President Franklin D. Roosevelt asked Congress to declare war against Japan following its attack on Pearl Harbor the day before. Swanson, the reading clerk, recorded the vote approving military action. Watch as he describes the atmosphere in the chamber, the decision by Montana Representative Jeannette Rankin to oppose the war, and his experience reading the declarations of war against Germany and Italy.

Chair of the Foreign Affairs Committee
Representative Ileana Ros-Lehtinen of Florida served as Chair of the House Foreign Affairs Committee.

The Honorable Ileana Ros-Lehtinen, U.S. Representative of Florida Interview recorded April 16, 2018 Transcript (PDF)