Amendment X

Document 1

Articles of Confederation, art. 2

Article II. Each state retains its sovereignty, freedom, and independence, and every Power, Jurisdiction and right, which is not by this confederation expressly delegated to the United States, in Congress assembled.

The Founders' Constitution
Volume 5, Amendment X, Document 1
http://press-pubs.uchicago.edu/founders/documents/amendXs1.html
The University of Chicago Press