Question: What was the military branch of service of the man who was President for the purchase of the state that the Aleutian Islands are a part of?

full_context: Document 1: Department of Alaska: The Department of Alaska was the designation for the government of Alaska from its purchase by the United States of America in 1867 until its organization as the District of Alaska in 1884. During the department era, Alaska was variously under the jurisdiction of the U.S. Army (until 1877), the U.S. Dept. of the Treasury (from 1877 until 1879) and the U.S. Navy (from 1879 until 1884). The area later became the District of Alaska, then the Territory of Alaska, then the State of Alaska.
Document 2: Lincoln (novel): Set during the American Civil War, the novel describes the presidency of Abraham Lincoln through the eyes of several historical figures, including presidential secretary John Hay, First Lady Mary Todd Lincoln, Secretary of State William H. Seward, Secretary of the Treasury Salmon Chase, his daughter Kate Chase, U.S. Representative Elihu B. Washburne, and conspirators John Wilkes Booth and David Herold.
Document 3: John Aaron Rawlins: John Aaron Rawlins (February 13, 1831 September 6, 1869) was a general officer in the Union Army during the American Civil War and a cabinet officer in the Grant administration. A longtime confidant of Ulysses S. Grant, Rawlins served on Grant's staff throughout the war, rising to the rank of brevet major general, and was Grant's chief defender against allegations of insobriety. He was appointed Secretary of War when Grant was elected President of the United States.
Document 4: Lafayette C. Baker: Lafayette Curry Baker (October 13, 1826 – July 3, 1868) was a United States investigator and spy, serving the Union Army, during the American Civil War and under Presidents Abraham Lincoln and Andrew Johnson.
Document 5: Alaska Purchase: The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by President Andrew Johnson.
Document 6: Alaska: With its myriad islands, Alaska has nearly 34,000 miles (54,720 km) of tidal shoreline. The Aleutian Islands chain extends west from the southern tip of the Alaska Peninsula. Many active volcanoes are found in the Aleutians and in coastal regions. Unimak Island, for example, is home to Mount Shishaldin, which is an occasionally smoldering volcano that rises to 10,000 feet (3,048 m) above the North Pacific. It is the most perfect volcanic cone on Earth, even more symmetrical than Japan's Mount Fuji. The chain of volcanoes extends to Mount Spurr, west of Anchorage on the mainland. Geologists have identified Alaska as part of Wrangellia, a large region consisting of multiple states and Canadian provinces in the Pacific Northwest, which is actively undergoing continent building.
Document 7: Geography of the United States: The West Coast of the continental United States and areas of Alaska (including the Aleutian Islands, the Alaskan Peninsula and southern Alaskan coast) make up part of the Pacific Ring of Fire, an area of heavy tectonic and volcanic activity that is the source of 90% of the world's earthquakes.[citation needed] The American Northwest sees the highest concentration of active volcanoes in the United States, in Washington, Oregon and northern California along the Cascade Mountains. There are several active volcanoes located in the islands of Hawaii, including Kilauea in ongoing eruption since 1983, but they do not typically adversely affect the inhabitants of the islands. There has not been a major life-threatening eruption on the Hawaiian islands since the 17th century. Volcanic eruptions can occasionally be devastating, such as in the 1980 eruption of Mount St. Helens in Washington.
Document 8: Reconstruction era: As Confederate states came back under control of the U.S. Army, President Abraham Lincoln set up reconstructed governments in Tennessee, Arkansas, and Louisiana during the war. He experimented by giving land to blacks in South Carolina. By fall 1865, the new President Andrew Johnson declared the war goals of national unity and the ending of slavery achieved and reconstruction completed. Republicans in Congress, refusing to accept Johnson's lenient terms, rejected new members of Congress, some of whom had been high - ranking Confederate officials a few months before. Johnson broke with the Republicans after vetoing two key bills that supported the Freedmen's Bureau and provided federal civil rights to the freedmen. The 1866 Congressional elections turned on the issue of Reconstruction, producing a sweeping Republican victory in the North, and providing the Radical Republicans with sufficient control of Congress to override Johnson's vetoes and commence their own ``Radical Reconstruction ''in 1867. That same year, Congress removed civilian governments in the South, and placed the former Confederacy under the rule of the U.S. Army. The army conducted new elections in which the freed slaves could vote, while whites who had held leading positions under the Confederacy were temporarily denied the vote and were not permitted to run for office.
Document 9: Catharinus P. Buckingham: Catharinus Putnam Buckingham (March 14, 1808 – August 30, 1888) was an American soldier, college professor, author, and industrialist. He served as a general in the Union Army during the American Civil War, and was the main assistant to the U.S. Secretary of War, Edwin M. Stanton, during part of the first term of the Lincoln Administration.
Document 10: Alaska Purchase: Russia continued to see an opportunity to weaken British power by causing British Columbia, including the Royal Navy base at Esquimalt, to be surrounded or annexed by American territory. Following the Union victory in the Civil War, the Tsar instructed the Russian minister to the United States, Eduard de Stoeckl, to re-enter into negotiations with William H. Seward in the beginning of March 1867. President Johnson was entangled in negotiations about Reconstruction and Seward had alienated a number of Republicans, so they believed that the purchase would help divert attention from the domestic issues. The negotiations concluded after an all - night session with the signing of the treaty at 04: 00 on March 30, 1867, with the purchase price set at $7.2 million ($105 million in 2016), or about 2 cents per acre ($4.74 / km).
Document 11: Alaska: Alaska is the northernmost and westernmost state in the United States and has the most easterly longitude in the United States because the Aleutian Islands extend into the eastern hemisphere. Alaska is the only non-contiguous U.S. state on continental North America; about 500 miles (800 km) of British Columbia (Canada) separates Alaska from Washington. It is technically part of the continental U.S., but is sometimes not included in colloquial use; Alaska is not part of the contiguous U.S., often called "the Lower 48". The capital city, Juneau, is situated on the mainland of the North American continent but is not connected by road to the rest of the North American highway system.
Document 12: Alaska Purchase: Russia continued to see an opportunity to weaken British power by causing British Columbia, including the Royal Navy base at Esquimalt, to be surrounded or annexed by American territory. Following the Union victory in the civil war, the Tsar instructed the Russian minister to the United States, Eduard de Stoeckl, to re-enter into negotiations with William Seward in the beginning of March 1867. President Johnson was entangled in negotiations about Reconstruction and Seward had alienated a number of Republicans, so they believed that the purchase would help divert attention from the current domestic matters. The negotiations concluded after an all - night session with the signing of the treaty at 04: 00 on March 30, 1867, with the purchase price set at $7.2 million ($123 million today), or about 2 cents per acre ($4.74 / km).
Document 13: Aleutian Islands: The Aleutian Islands (Aleut: Tanam Unangaa, literally ``Land of the Aleuts ''; pronounced (/ əˈluːʃən /; possibly from Chukchi aliat,`` island'') are a chain of 14 large volcanic islands and 55 smaller ones belonging to both the U.S. state of Alaska and the Russian federal subject of Kamchatka Krai. They form part of the Aleutian Arc in the Northern Pacific Ocean, occupying an area of 6,821 sq mi (17,666 km) and extending about 1,200 mi (1,900 km) westward from the Alaska Peninsula toward the Kamchatka Peninsula in Russia, and mark a dividing line between the Bering Sea to the north and the Pacific Ocean to the south. Crossing longitude 180 °, at which point east and west longitude end, the archipelago contains both the westernmost part of the United States by longitude (Amatignak Island) and the easternmost by longitude (Semisopochnoi Island). The westernmost U.S. island in real terms, however, is Attu Island, west of which runs the International Date Line. While nearly all the archipelago is part of Alaska and is usually considered as being in the ``Alaskan Bush '', at the extreme western end, the small, geologically related Commander Islands belong to Russia.
Document 14: Volcanic arc: Two classic examples of oceanic island arcs are the Mariana Islands in the western Pacific Ocean and the Lesser Antilles in the western Atlantic Ocean. The Cascade Volcanic Arc in western North America and the Andes along the western edge of South America are examples of continental volcanic arcs. The best examples of volcanic arcs with both sets of characteristics are in the North Pacific, with the Aleutian Arc consisting of the Aleutian Islands and their extension the Aleutian Range on the Alaska Peninsula, and the Kuril - Kamchatka Arc comprising the Kuril Islands and southern Kamchatka Peninsula.
Document 15: Alaska Purchase: The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by president Andrew Johnson.
ground_truth: Union Army
sub_queries: the aleutian islands are part of which state Answer: Alaska
who was the president when Alaska was purchased Answer: Andrew Johnson
Andrew Johnson >> military branch Answer: Union Army