Quotation: "I stretched the Constitution until it cracked."1

Variations: None known.

Sources consulted:

1. Founders Online
2. Thomas Jefferson Retirement Papers
3. Google Books
4. Hathi Trust
5. 19th Century U.S. Newspapers database
6. Access Newspaper Archive
7. American Periodicals Series

Earliest appearance in print: A. O. Wright, An Exposition of the Constitution of the United States, 7th ed., (Madison, WI: Midland Publishing Co., 1883), 238.

Earliest appearance in print, attributed to Thomas Jefferson: See above.

Comments: This statement has not been found in the writings of Thomas Jefferson.  Most sources connect it to the Louisiana Purchase.  Many claim that it was a comment made by Jefferson to Congress in announcing the purchase (likely referring to Jefferson's Third Annual Message to Congress), but no such comment appears in that document.2

• 1. Note: The quotation usually appears without "I;" e.g. "Thomas Jefferson said that he 'stretched the Constitution until it cracked.'"
• 2. The Avalon Project.  Thomas Jefferson.  Third Annual Message, October 17, 1803.