Section 8

... of the Constitution of The United States of America says:

Section 8 - Powers of Congress
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
To borrow money on the credit of the United States;
To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes;
To establish an uniform Rule of Naturalization, and uniform Laws on the subject of Bankruptcies throughout the United States;
To coin Money, regulate the Value thereof, and of foreign Coin, and fix the Standard of Weights and Measures;
To provide for the Punishment of counterfeiting the Securities and current Coin of the United States;
To establish Post Offices and Post Roads;
To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;
To constitute Tribunals inferior to the supreme Court;
To define and punish Piracies and Felonies committed on the high Seas, and Offenses against the Law of Nations;
To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water;
To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years;
To provide and maintain a Navy;
To make Rules for the Government and Regulation of the land and naval Forces;
To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;
To provide for organizing, arming, and disciplining the Militia, and for governing such Part of them as may be employed in the Service of the United States, reserving to the States respectively, the Appointment of the Officers, and the Authority of training the Militia according to the discipline prescribed by Congress;
To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings; And
To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.

Let's take this step by step:

1. The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises... - To most people this looks like blanket permission for Congress to tax us however they wish. Understand that FedGov is only supposed to be able to do those things which are specifically authorized. That paragraph goes on to state the purpose of those taxes.
2. ...pay the Debts and provide for the common Defence and general Welfare of the United States... - Everyone knows about the General Welfare clause, it's been used to expand government to no end. But here's something I never really noticed before; it says "the general Welfare of the United States," NOT "the People of the United States." I'm not a Consitutional scholar but to me that is simply talking about the governing infrastructure of the states in order to keep the political machinary functioning properly to maintain the Republic so the states can fulfill their appointed duties according the rest of the Constitution.
3. ..but all Duties, Imposts and Excises shall be uniform throughout the United States; - Uniform? Note though it doesn't say taxes have to be uniform, just the duties, imposts and excises. Anyone know what an 'impost' is? Note, this part does not actually authorize an income tax. That came later and if you do a little digging, it's appears it wasn't ratified properly.
4. To borrow money on the credit of the United States; - Keep it in context; only for authorized activities. I'm sure that "inflating the money supply" is not an authorized activity.
5. To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes; - Notice this doesn't say "regulate the commerce OF the States. This is another one of those clauses that has stretched the bounds of credulity. There are lots of regulations that fall under the auspices of the Commerce Clause that have no business being there. A while back there was a man in Texas who was put on trial for a firearms violation for bringing a gun near a school. He was tried under the Commerce Clause. The state dismissed the charges so he could be tried at Federal level. Fortunately, the judge had some sense and the charges were dismissed. Note, he likely would have been convicted had the state not bumped it up to the Fed.
6. To establish an uniform Rule of Naturalization, and uniform Laws on the subject of Bankruptcies throughout the United States; - Unfortunately, it says nothing about uniform ENFORCEMENT.
7. To coin Money, regulate the Value thereof, and of foreign Coin, and fix the Standard of Weights and Measures; - The Consitution also defines money. What we have now is not money, it's debt. Look at a dollar bill; it says "Federal Reserve Note." A note is a debt, nothing more. If the entire Federal debt was paid off tomorrow, your "money" would be worth nothing. Wrap your head around that one kids.
8. To provide for the Punishment of counterfeiting the Securities and current Coin of the United States; - Other than trying to prosecute the guy that was printing gospel tracts that looked like $1,000,000,000 bills (which the U.S. does not issue), I haven't seen too many violations of that law. Then again, the 'money' in your pocket is the property of the Federal Reserve, so it's neither a United States security nor coinage. Wouldn't that be an interesting challenge to the law.
9. To establish Post Offices and Post Roads; - I never could quite fathom why the authors thought that post offices were a valid function of the Federal Government. I'd have to do some digging, but I'd be almost willing to bet, it referred to post offices and related roads specifically to deliver mail to the government and not the system we have today. If you happen to know anything about this, please enlighten me.
10. To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries; - Please notice this says nothing about subsidizing said activities. And it only says to promote the Progress thereof, not the science and useful arts themselves.
11. To constitute Tribunals inferior to the supreme Court; - I'm not sure what to make of this. Have there been any abuses related to this clause? To constitute tribunals for what purpose?
12. To define and punish Piracies and Felonies committed on the high Seas, and Offenses against the Law of Nations; - Notice this doesn't say anything about regulating commerce on the high seas the way the LOST treaty specifies.
13. To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water; - It says nothing about giving the Congress the power to deleagate war making powers to the President the way the War Powers Act has done.
14. To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years; - Read that very carefully; we're NOT supposed to have a standing Army. That was always seen as a danger to liberty. Armies have historically been abused to subjugate the governed rather than just fight wars and defend the borders.
15. To provide and maintain a Navy; - Navy.. water... protect us against attack. Fine.
16. To make Rules for the Government and Regulation of the land and naval Forces; - As much as it galls me to have Congress armchair quarterbacking the military, it provides for proper checks and balances. Congress represents us which means the military doesn't become a law unto itself and take over.
17. To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions; - Armies are supposed to travel to a war, militias are supposed to defend us within our own borders. Where is our militia? It's supposed to be us. No, the National Guard is not a militia, it's a standing Army.
18. To provide for organizing, arming, and disciplining the Militia, and for governing such Part of them as may be employed in the Service of the United States, reserving to the States respectively, the Appointment of the Officers, and the Authority of training the Militia according to the discipline prescribed by Congress; - That's all a bit more vague than I'd like it to be. Almost sounds like Congress is supposed to help the states organize their own militias and give us guns. WOOHOO! Yeah, like that's going to happen.
19. To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings; And... - This authorized the building of Washington, D.C. Maybe it's just me, but I'm not so sure anyone was supposed to actually LIVE in the District. We were never supposed to have citizens of the Fed, just the states. Imagine if we kicked everyone out of D.C. in terms of actual residence. Talk about urban renewal!
20. To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof. - ..."AND PROPER..."

It's sad how far we've fallen.