What is the difference between Article II courts and Article III courts?

Answer 1

Federal courts in the United States are sometimes classified as "Article I courts," "Article II courts" and "Article III courts," in reference to the first three articles of the U.S. Constitution:

Article I addresses the legislative power of the federal government, which includes Congress's power over non-state territories (e.g., American Samoa). Article I courts include territorial courts (U.S. District Court for the Virgin Islands, for example), and also some specialized courts created by Congress for specific purposes (such as the United States Tax Court and the United States Court of Military Appeals). Judges of Article I courts generally do not have the constitutional protections of life tenure or salary protection, and are instead often appointed for fixed terms (such as 10 or 14 years).

Article II addresses the executive power of the federal government, which includes the President's power as commander in chief. The term "Article II court" is rarely used (and there isn't really a solid distinction between an "Article I court" and an "Article II court"), but military courts martial are sometimes considered Article II courts. So, too, are military commissions, and the anomalous U.S. Court for Berlin. (Note, by contrast, the U.S. Court for China, which is considered an Article I court.)

Article III addresses the judicial power of the federal government. The vast majority of federal courts are "Article III courts," including the U.S. Supreme Court, the various U.S. Courts of Appeals (for the First, Second, Third, Fourth, Fifth, Sixth, Seventh, Eighth, Ninth, Tenth, Eleventh, D.C. and Federal Circuits), and all of the United States District Courts other than the territorial courts. The U.S. Court of International Trade is also an Article III court. Judges of Article III courts enjoy salary protection and life tenure (that is, they may only be removed by impeachment and conviction).

Answer 2

Article III judges serve for life during good behavior and their compensation may not be reduced during service. Article I judges do not have these protections.