user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: What politician who started his governmental position prior to 2 January 1939 was the leader of the United States during WWII? 
Knowledge Triplets: George Washington, first President of the United States, common.image.appears_in_topic_gallery, Charles Lee
President of the United States, freebase.type_profile.equivalent_topic, US President
Gestapo, organization.organization.founders, Adolf Hitler
m.03fx83k, government.government_position_held.office_position_or_title, President of the United States
Lyndon B. Johnson, government.us_vice_president.to_president, John F. Kennedy
President of the United States, government.government_office_or_title.office_holders, m.04s_2dh
Peter Rodman, book.author.works_written, Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush
m.0446b9r, government.government_position_held.office_position_or_title, President of the United States
President of the United States, government.government_office_or_title.category, President
Jimmy Carter, government.politician.government_positions_held, m.0446b70
m.02h6phn, government.government_position_held.office_holder, George W. Bush
Charles Lee, common.topic.image, George Washington, first President of the United States
John F. Kennedy, government.us_president.vice_president, Lyndon B. Johnson
John Quincy Adams, people.person.profession, Politician
Carl Gustaf Emil Mannerheim, military.military_person.participated_in_conflicts, World War II
John Adams, government.politician.government_positions_held, m.04466xb
m.04466zr, government.government_position_held.office_position_or_title, President of the United States
Millard Fillmore, government.us_vice_president.to_president, Zachary Taylor
m.04466xb, government.government_position_held.office_holder, John Adams
Calvin Coolidge, government.politician.government_positions_held, m.0446b9r
John Adams, government.us_president.vice_president, Thomas Jefferson
President of the United States, common.topic.webpage, m.09y93hy
President Pennybaker, book.written_work.subjects, President of the United States
m.04469xf, government.government_position_held.office_position_or_title, President of the United States
George W. Bush, government.politician.government_positions_held, m.02h6phn
Abraham Lincoln, government.us_president.vice_president, Andrew Johnson
President of the United States, common.topic.notable_types, Government Office or Title
Lyndon B. Johnson, people.person.nationality, United States of America
m.02hz5r6, government.government_position_held.office_position_or_title, President of the United States
President of the United States, common.topic.webpage, m.09wvy_x
President of the United States, common.topic.webpage, m.09ygxjq
Warren G. Harding, common.topic.notable_types, US President
m.03fx8cf, government.government_position_held.office_holder, Richard Nixon
George Washington, first President of the United States, common.image.appears_in_topic_gallery, President of the United States
Bill Clinton, government.politician.government_positions_held, m.02k6vpl
m.03fx8cf, government.government_position_held.office_position_or_title, President of the United States
President of the United States, common.topic.webpage, m.09xgz2n
George H. W. Bush, government.politician.government_positions_held, m.01xrx8q
Mediterranean and Middle East theatre of World War II, base.culturalevent.event.entity_involved, Benito Mussolini
m.03fx83k, government.government_position_held.office_holder, William Howard Taft
John Adams, people.person.profession, Politician
Josip Broz Tito, military.military_person.participated_in_conflicts, World War II
President of the United States, common.topic.notable_for, g.125734vfj
President of the United States, government.government_office_or_title.office_holders, m.03fx88b
Harry S. Truman, government.us_vice_president.to_president, Franklin D. Roosevelt
m.04469yh, government.government_position_held.office_position_or_title, President of the United States
William Howard Taft, government.politician.government_positions_held, m.03fx83k
m.04469y1, government.government_position_held.office_position_or_title, President of the United States
President of the United States, base.firsts.achievement.firsts, m.04xdfjz
George Washington, government.us_president.vice_president, John Adams
President of the United States, government.government_office_or_title.office_holders, m.0446bdk
Herbert Hoover, government.politician.government_positions_held, m.0446b9j
President of the United States, government.government_office_or_title.office_holders, m.03fx817
Ronald Reagan, military.military_person.participated_in_conflicts, World War II
President of the United States, common.topic.webpage, m.0b464_j
President of the United States, common.topic.webpage, m.0b46f7h
Adolf Hitler, military.military_person.participated_in_conflicts, World War I
Joseph Goebbels, common.topic.notable_types, Politician
m.04466zr, government.government_position_held.office_holder, Andrew Jackson
m.03fx81_, government.government_position_held.office_position_or_title, President of the United States
m.09xgz2n, common.webpage.topic, President of the United States
John Tyler, government.us_vice_president.to_president, William Henry Harrison
Barack Obama, government.politician.government_positions_held, m.04s_2dh
m.04s_2dh, government.government_position_held.office_position_or_title, President of the United States
President of the United States, base.firsts.achievement.firsts, m.04wrwjv
m.0446b70, government.government_position_held.office_position_or_title, President of the United States
Richard Nixon, government.us_president.vice_president, Gerald Ford
m.0446b9j, government.government_position_held.office_holder, Herbert Hoover
President of the United States, government.government_office_or_title.office_holders, m.0446b9j
World War II, event.speech_or_presentation.speech_topic, m.05rln07
President of the United States, common.topic.webpage, m.09w6pyk
Theodore Roosevelt, people.person.nationality, United States of America
m.0b464_j, common.webpage.topic, President of the United States
m.0446b70, government.government_position_held.office_holder, Jimmy Carter
President of the United States, government.government_office_or_title.office_holders, m.03fx82m
m.03fx7_v, government.government_position_held.office_holder, Benjamin Harrison
Abraham Lincoln, government.politician.government_positions_held, m.0446bdb
President of the United States, government.government_office_or_title.office_holders, m.04469y1
President of the United States, government.government_office_or_title.office_holders, m.03fx7hy
James A. Garfield, government.us_president.vice_president, Chester A. Arthur
Zachary Taylor, government.us_president.vice_president, Millard Fillmore
m.0hnjbwk, common.webpage.topic, President of the United States
m.03q2h_9, government.government_position_held.office_position_or_title, President of the United States
President of the United States, common.topic.webpage, m.09ysj6g
m.0446b8l, government.government_position_held.office_holder, Dwight D. Eisenhower
United States of America, people.person.nationality, Franklin D. Roosevelt
m.03fx7j8, government.government_position_held.office_holder, Grover Cleveland
m.05rln07, event.speech_or_presentation.speaker_s, Franklin D. Roosevelt
Harry S. Truman, government.politician.government_positions_held, m.03fx817
Gerald Ford, government.politician.government_positions_held, m.03fx7zy
President of the United States, base.schemastaging.context_name.plural, m.0w0qt9b
President of the United States, fictional_universe.character_occupation.characters_with_this_occupation, Josiah Bartlet
President of the United States, common.topic.webpage, m.04lsvx0
Lyndon B. Johnson, people.person.profession, Politician
m.03fx88b, government.government_position_held.office_position_or_title, President of the United States
m.03fx7j8, government.government_position_held.office_position_or_title, President of the United States
President of the United States, fictional_universe.character_occupation.characters_with_this_occupation, President Thomas Westwood
President of the United States, common.topic.image, George Washington, first President of the United States
Richard Nixon, military.military_person.participated_in_conflicts, World War II
World War, 1939-1945--Hostages, base.skosbase.skos_concept.in_scheme, Authorities Concept Scheme
President of the United States, government.government_office_or_title.jurisdiction, United States of America
Richard Nixon, government.politician.government_positions_held, m.03fx8cf
President of the United States, government.government_office_or_title.office_holders, m.03fx8cf
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, book.written_work.subjects, Politics of the United States
Edward Rydz-Śmigły, military.military_person.participated_in_conflicts, World War II
m.0b46f7h, common.webpage.topic, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx899
m.01xrx8q, government.government_position_held.office_position_or_title, President of the United States
m.0446b9j, government.government_position_held.office_position_or_title, President of the United States
Ronald Reagan, government.us_president.vice_president, George H. W. Bush
m.04469y8, government.government_position_held.office_holder, James K. Polk
Joseph Goebbels, people.person.profession, Politician
Richard Nixon, people.person.nationality, United States of America
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, common.topic.notable_for, g.125f9cm5z
President of the United States, common.topic.webpage, m.09xlnpm
m.03fx87q, government.government_position_held.office_holder, William Henry Harrison
President of the United States, government.government_office_or_title.office_holders, m.02kzpyv
Benito Mussolini, military.military_person.participated_in_conflicts, World War II
Calvin Coolidge, government.us_vice_president.to_president, Warren G. Harding
John F. Kennedy, military.military_person.participated_in_conflicts, World War II
Martin Van Buren, government.us_vice_president.to_president, Andrew Jackson
Andrew Jackson, government.us_president.vice_president, Martin Van Buren
m.04466xm, government.government_position_held.office_position_or_title, President of the United States
John Adams, government.us_vice_president.to_president, George Washington
m.09w6pyk, common.webpage.topic, President of the United States
George Washington, first President of the United States, common.image.appears_in_topic_gallery, The Imperial Presidency
m.03fx7_v, government.government_position_held.office_position_or_title, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx87q
Dwight D. Eisenhower, government.politician.government_positions_held, m.0446b8l
President of the United States, government.government_office_or_title.office_holders, m.02k6vpl
Thomas Jefferson, government.politician.government_positions_held, m.03fx8bt
m.0446b9r, government.government_position_held.office_holder, Calvin Coolidge
Richard Nixon, government.us_vice_president.to_president, Dwight D. Eisenhower
Richard Nixon, people.person.profession, Politician
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, book.book.genre, Non-fiction
m.03fx83v, government.government_position_held.office_position_or_title, President of the United States
m.03fx81_, government.government_position_held.office_holder, Lyndon B. Johnson
m.02kzpyv, government.government_position_held.office_position_or_title, President of the United States
United States of America, government.governmental_jurisdiction.government_positions, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx81_
Dwight D. Eisenhower, military.military_person.participated_in_conflicts, World War II
Chester A. Arthur, government.us_vice_president.to_president, James A. Garfield
m.05ckhcc, common.webpage.topic, President of the United States
Andrew Johnson, government.us_vice_president.to_president, Abraham Lincoln
Grover Cleveland, government.politician.government_positions_held, m.03fx7hy
Theodore Roosevelt, government.politician.government_positions_held, m.03fx899
m.03fx7zy, government.government_position_held.office_position_or_title, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx88m
Dwight D. Eisenhower, military.military_person.participated_in_conflicts, World War I
m.03q2h_9, government.government_position_held.office_holder, Franklin D. Roosevelt
President of the United States, book.book_subject.works, The Sound of Leadership: Presidential Communication in the Modern Age
President of the United States, common.topic.article, m.060dd
President of the United States, book.book_subject.works, President Pennybaker
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, common.topic.notable_types, Book
President of the United States, common.topic.webpage, m.0hnjbwk
Joseph Stalin, people.person.profession, Politician
Dwight D. Eisenhower, government.us_president.vice_president, Richard Nixon
Maurice Gamelin, military.military_person.participated_in_conflicts, World War II
Adolf Hitler, people.person.profession, Politician
Josiah Bartlet, fictional_universe.fictional_character.occupation, President of the United States
m.0663zsk, common.webpage.topic, President of the United States
George Washington, government.politician.government_positions_held, m.02s9flj
President of the United States, book.book_subject.works, The American Leadership Tradition: Moral Vision from Washington to Clinton
Warren G. Harding, people.person.profession, Politician
President of the United States, government.government_office_or_title.office_holders, m.04469yh
William Henry Harrison, government.us_president.vice_president, John Tyler
m.03fx8c3, government.government_position_held.office_position_or_title, President of the United States
George Washington, first President of the United States, common.image.appears_in_topic_gallery, George Washington
m.03fx838, government.government_position_held.office_position_or_title, President of the United States
m.0446bdb, government.government_position_held.office_position_or_title, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx83v
Franklin D. Roosevelt, government.us_president.vice_president, Harry S. Truman
m.09y9g34, common.webpage.topic, President of the United States
m.02h6phn, government.government_position_held.office_position_or_title, President of the United States
Władysław Sikorski, military.military_person.participated_in_conflicts, World War II
President of the United States, government.government_office_or_title.office_holders, m.04466xm
William McKinley, government.us_president.vice_president, Theodore Roosevelt
m.04466tx, government.government_position_held.office_position_or_title, President of the United States
James Monroe, government.politician.government_positions_held, m.04466xz
m.09ygxjq, common.webpage.topic, President of the United States
President of the United States, common.topic.webpage, m.09ynr7x
President of the United States, common.topic.webpage, m.09y9g34
Ulysses S. Grant, government.politician.government_positions_held, m.03fx88m
m.0446b8l, government.government_position_held.office_position_or_title, President of the United States
George H. W. Bush, military.military_person.participated_in_conflicts, World War II
President of the United States, government.government_office_or_title.office_holders, m.0446bdb
President of the United States, government.government_office_or_title.jurisdiction, United States of America
Dwight D. Eisenhower, people.person.profession, Politician
m.03fx85y, government.government_position_held.office_holder, William McKinley
John Tyler, government.politician.government_positions_held, m.04469xv
m.03q2h_9, government.government_position_held.office_holder, Franklin D. Roosevelt
m.04466xb, government.government_position_held.office_position_or_title, President of the United States
m.02k6vpl, government.government_position_held.office_holder, Bill Clinton
m.09ysj6g, common.webpage.topic, President of the United States
m.03fx7hy, government.government_position_held.office_position_or_title, President of the United States
George H. W. Bush, government.us_vice_president.to_president, Ronald Reagan
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, book.written_work.subjects, Foreign policy
m.09xlnpm, common.webpage.topic, President of the United States
Benjamin Harrison, government.politician.government_positions_held, m.03fx7_v
1940s, common.topic.image, World War II montage image
Zachary Taylor, government.politician.government_positions_held, m.03fx83v
Lyndon B. Johnson, government.politician.government_positions_held, m.03fx81_
m.04466tx, government.government_position_held.office_holder, Andrew Johnson
President of the United States, government.government_office_or_title.office_holders, m.0446bcc
James Madison, government.politician.government_positions_held, m.04466xm
President of the United States, base.firsts.achievement.firsts, m.04wrx4g
President of the United States, government.government_office_or_title.office_holders, m.0446b70
George H. W. Bush, people.person.profession, Politician
Gerald Ford, government.us_vice_president.to_president, Richard Nixon
m.02s9flj, government.government_position_held.office_position_or_title, President of the United States
Lyndon B. Johnson, military.military_person.participated_in_conflicts, World War II
m.04466xz, government.government_position_held.office_position_or_title, President of the United States
Martin Van Buren, government.politician.government_positions_held, m.04469xf
Theodore Roosevelt, people.person.profession, Historian
m.03fx838, government.government_position_held.office_holder, Woodrow Wilson
m.02kzpyv, government.government_position_held.office_holder, Ronald Reagan
m.04469y8, government.government_position_held.office_position_or_title, President of the United States
Gerald Ford, military.military_person.participated_in_conflicts, World War II
President of the United States, government.government_office_or_title.office_holders, m.03fx838
President of the United States, government.government_office_or_title.office_holders, m.02h6phn
World War I, base.culturalevent.event.entity_involved, Woodrow Wilson
m.04469xv, government.government_position_held.office_position_or_title, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx85y
Millard Fillmore, government.politician.government_positions_held, m.04469yh
President of the United States, government.government_office_or_title.office_holders, m.04466zr
Thomas Jefferson, government.us_vice_president.to_president, John Adams
Theodore Roosevelt, government.us_vice_president.to_president, William McKinley
President of the United States, base.schemastaging.context_name.pronunciation, g.125_lw0zw
m.03fx87q, government.government_position_held.office_position_or_title, President of the United States
James A. Garfield, government.politician.government_positions_held, m.03fx82m
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, common.topic.image, command.jpg
Warren G. Harding, people.person.nationality, United States of America
Andrew Johnson, government.politician.government_positions_held, m.04466tx
m.04lsvx0, common.webpage.topic, President of the United States
George Washington, first President of the United States, common.image.appears_in_topic_gallery, Powers of the President of the United States
President of the United States, government.government_office_or_title.office_holders, m.04469xf
President of the United States, government.government_office_or_title.office_holders, m.04469xv
James Buchanan, government.politician.government_positions_held, m.04469y1
m.03fx8bt, government.government_position_held.office_position_or_title, President of the United States
William Howard Taft, people.person.nationality, United States of America
Presidential Leadership: Rating the Best and the Worst in the White House, book.written_work.subjects, President of the United States
m.0446bdk, government.government_position_held.office_position_or_title, President of the United States
Mediterranean and Middle East theatre of World War II, base.culturalevent.event.entity_involved, Dwight D. Eisenhower
John F. Kennedy, government.politician.government_positions_held, m.02hz5r6
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, book.written_work.subjects, President of the United States
President of the United States, common.topic.webpage, m.09xm31x
President of the United States, common.topic.webpage, m.05ckhcc
World War, 1939-1945--Hostages, base.skosbase.skos_concept.in_scheme, Topical Terms Concept Scheme
Woodrow Wilson, government.politician.government_positions_held, m.03fx838
President of the United States, government.government_office_or_title.office_holders, m.03fx8bt
President of the United States, book.book_subject.works, Presidential Leadership: Rating the Best and the Worst in the White House
m.09wvy_x, common.webpage.topic, President of the United States
President of the United States, government.government_office_or_title.office_holders, m.0446b8l
Woodrow Wilson, people.person.nationality, United States of America
President of the United States, government.government_office_or_title.office_holders, m.04466xb
m.03fx85y, government.government_position_held.office_position_or_title, President of the United States
Theodore Roosevelt, people.person.profession, Politician
Franklin D. Roosevelt, government.politician.government_positions_held, m.03q2h_9
US President, common.topic.notable_types, Franklin D. Roosevelt
President of the United States, book.book_subject.works, Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush
m.040b_7k, government.government_position_held.office_position_or_title, President of the United States
m.02hz5r6, government.government_position_held.office_holder, John F. Kennedy
m.0446bcc, government.government_position_held.office_position_or_title, President of the United States
1940s, time.event.includes_event, World War II
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, book.written_work.author, Peter Rodman
m.03fx82m, government.government_position_held.office_position_or_title, President of the United States
George Washington, common.topic.image, George Washington, first President of the United States
President of the United States, common.topic.webpage, m.0663zsk
President of the United States, government.government_office_or_title.office_holders, m.03fx7j8
George W. Bush, people.person.profession, Politician
m.03fx88m, government.government_position_held.office_holder, Ulysses S. Grant
Presidential Command: Power, Leadership, and the Making of Foreign Policy from Richard Nixon to George W. Bush, common.topic.article, m.063t8my
President of the United States, government.government_office_or_title.office_holders, m.040b_7k
President of the United States, government.government_office_or_title.office_holders, m.01xrx8q
m.02k6vpl, government.government_position_held.office_position_or_title, President of the United States
m.04466xz, government.government_position_held.office_holder, James Monroe
George Washington, first President of the United States, common.image.appears_in_topic_gallery, Town Destroyer
Rutherford B. Hayes, government.politician.government_positions_held, m.03fx8c3
Mediterranean and Middle East theatre of World War II, base.culturalevent.event.entity_involved, Adolf Hitler
m.09ynr7x, common.webpage.topic, President of the United States
Franklin Pierce, government.politician.government_positions_held, m.0446bdk
Ronald Reagan, government.politician.government_positions_held, m.02kzpyv
Warren G. Harding, government.politician.government_positions_held, m.03fx88b
Andrew Jackson, government.politician.government_positions_held, m.04466zr
m.04466xm, government.government_position_held.office_holder, James Madison
Chester A. Arthur, government.politician.government_positions_held, m.0446bcc
m.03fx899, government.government_position_held.office_position_or_title, President of the United States
George Washington, first President of the United States, common.image.appears_in_topic_gallery, Presidency of George Washington
m.09y93hy, common.webpage.topic, President of the United States
m.03fx8c3, government.government_position_held.office_holder, Rutherford B. Hayes
Charles de Gaulle, military.military_person.participated_in_conflicts, World War II
Franklin D. Roosevelt, people.person.profession, Politician
m.03fx7zy, government.government_position_held.office_holder, Gerald Ford
President of the United States, government.government_office_or_title.office_holders, m.03fx7_v
President of the United States, base.firsts.achievement.firsts, m.08ntjg4
m.03fx8bt, government.government_position_held.office_holder, Thomas Jefferson
Grover Cleveland, government.politician.government_positions_held, m.03fx7j8
President of the United States, government.government_office_or_title.office_holders, m.03q2h_9
President of the United States, government.government_office_or_title.office_holders, m.0446b9r
m.03fx88b, government.government_position_held.office_holder, Warren G. Harding
President of the United States, government.government_office_or_title.office_holders, m.04469y8
m.03fx899, government.government_position_held.office_holder, Theodore Roosevelt
John Quincy Adams, government.politician.government_positions_held, m.040b_7k
President of the United States, government.government_office_or_title.office_holders, m.03fx8c3
President of the United States, government.government_office_or_title.office_holders, m.04466xz
m.03fx817, government.government_position_held.office_position_or_title, President of the United States
President of the United States, common.topic.webpage, m.09w6h41
President of the United States, government.government_office_or_title.office_holders, m.03q2h_9
United States of America, government.governmental_jurisdiction.government_positions, Vice President of the United States
President of the United States, government.government_office_or_title.office_holders, m.03fx83k
James K. Polk, government.politician.government_positions_held, m.04469y8
m.040b_7k, government.government_position_held.office_holder, John Quincy Adams
President of the United States, government.government_office_or_title.office_holders, m.03fx7zy
m.04469y1, government.government_position_held.office_holder, James Buchanan
President of the United States, government.government_office_or_title.office_holders, m.02hz5r6
m.03fx817, government.government_position_held.office_holder, Harry S. Truman
Warren G. Harding, government.us_president.vice_president, Calvin Coolidge
World War, 1939-1945--Hostages, base.skosbase.skos_concept.broader_topic, World War II
George Washington, first President of the United States, common.image.size, m.02f0j1t
President of the United States, government.government_office_or_title.office_holders, m.04466tx
Adolf Hitler, people.person.profession, Soldier
m.09w6h41, common.webpage.topic, President of the United States
m.09xm31x, common.webpage.topic, President of the United States
Dwight D. Eisenhower, people.person.nationality, United States of America
Woodrow Wilson, people.person.profession, Politician
President of the United States, government.government_office_or_title.office_holders, m.02s9flj
m.03fx7hy, government.government_position_held.office_holder, Grover Cleveland
President Thomas Westwood, fictional_universe.fictional_character.occupation, President of the United States
m.03fx88m, government.government_position_held.office_position_or_title, President of the United States
William McKinley, government.politician.government_positions_held, m.03fx85y
William Henry Harrison, government.politician.government_positions_held, m.03fx87q
m.01xrx8q, government.government_position_held.office_holder, George H. W. Bush

Answer: Franklin D. Roosevelt