When TIME asked nine presidential historians to rank, from best to worst, the 17 American Presidents of the 20th century, we left some questions to their discretion: What do we expect from our leaders? Are effective Presidents also the most significant ones? What constitutes greatness? Here is our panel's consensus:
1 FRANKLIN D. ROOSEVELT
Chief accomplishments: Rescued country from Depression; led U.S. through its greatest foreign war
Biggest blunder: Tried to "pack" the Supreme Court in 1937
Historians' comments: "Changed the landscape of American life"; "In a class by himself"; "Indisputably the century's greatest"
2 THEODORE ROOSEVELT