1. Lay and collect taxes, duties, imposts, and excises (to pay debts and provide for the common defense and general welfare). Uniform throughout the United States. 2. Borrow money on the credit of the United States. 3. Regulate commerce with foreign nations, among the states, and with Indian tribes. 4. Establish a uniform rule of naturalization and uniform bankruptcy laws. 5. Coin money, regulate its value and that of foreign coin, and fix the standard of weights and measures. 6. Punish counterfeiting of U.S. securities and coin. 7. Establish post offices and post roads. 8. Promote science and useful arts by securing limited-term exclusive rights to authors and inventors (patents and copyrights). 9. Constitute tribunals inferior to the Supreme Court. 10. Define and punish piracies and felonies on the high seas and offenses against the law of nations. 11. Declare war, grant letters of marque and reprisal, and make rules on captures on land and water. 12. Raise and support armies (appropriations limited to two years). 13. Provide and maintain a navy. 14. Make rules for the government and regulation of the land and naval forces. 15. Call forth the militia to execute federal laws, suppress insurrections, and repel invasions. 16. Organize, arm, and discipline the militia, and govern the part in federal service (states appoint officers and train the militia under congressional discipline). 17. Exercise exclusive legislation over the District of Columbia and over places purchased for forts, arsenals, dockyards, and other needful buildings (with state consent). 18. Make all laws necessary and proper for carrying into execution the foregoing powers and all other powers vested by the Constitution in the federal government (the Necessary and Proper Clause).