Explain the difference.

28 U.S. Code § 1746 - Unsworn declarations under penalty of perjury

(1)
If executed without the United States: “I declare (or certify, verify, or state) under penalty of perjury under the laws of the United States of America that the foregoing is true and correct. Executed on (date).
(Signature)”.
(2)
If executed within the United States, its territories, possessions, or commonwealths: “I declare (or certify, verify, or state) under penalty of perjury that the foregoing is true and correct. Executed on (date).
(Signature)”.

Which one do you use on all government contracts?