Second Amendment Sovereignty Act of 2012 - Expresses the sense of Congress that U.S. sovereignty and the constitutionally protected freedoms of American gun owners must be upheld and not be undermined by a United Nations Arms Trade Treaty.
Prohibits funds from being obligated or expended to use U.S. influence, in connection with negotiations for a United Nations Arms Trade Treaty, to restrict the rights of U.S. citizens under the second amendment to the Constitution, or to otherwise regulate domestic manufacture, assembly, possession, use, transfer, or purchase of firearms, ammunition, or related items.