Consider the following quote:

"It would reduce the whole instrument to a single phrase, that of instituting a Congress with power to do whatever would be for the good of the United States; and as they would be the sole judges of the good or evil, it would be also a power to do whatever evil they please. Certainly no such universal power was meant to be given them. It [the Constitution] was intended to lace them up straightly within the enumerated powers and those without which, as means, these powers could not be carried into effect."

-- Thomas Jefferson (Opinion on a National Bank, 15 February 1791)

The historical context of this quote concerns a debate over whether Congress was Constitutionally authorized to create a national bank. Jefferson and Madison opposed the measure, but Congress did eventually pass a law creating the bank. Washington was aware of Jefferson's position, but he remained uncertain about the Constitutionality of the bill. So, he asked his Secretary of the Treasury, Alexander Hamilton, upon whose intellect Washington often depended, for his opinion on the matter. Hamilton produced an argument for what he called "implied powers" inherent in the Constitution. Hamilton's essay can be viewed here.

Hamilton's argument (or at least, his initial argument -- I have not read his entire essay) is that the powers laid out in the Constitution are "ends," or "goals" of Congress. It would not make sense if Congress were given these goals, but no means to accomplish them. Therefore, said Hamilton, the Constitution implies the power to accomplish its explicitly stated goals. Hence, "implied powers." Washington accepted Hamilton's argument (as he usually did) and signed the bill into law.

Now, there are two things I want to point out about this situation. First, as I read the quote from Jefferson, I noticed the following statement:

It [the Constitution] was intended to lace them up straightly within the enumerated powers and those without which, as means, these powers could not be carried into effect. (emphasis mine)

It would appear from this quote that Jefferson recognized the necessity of "implied powers" as well. He conceded that it is nonsensical to ascribe the power to "regulate interstate commerce" to Congress, but then toss out any law attempting to do so because the means utilized in the law are not enumerated in the Constitution. The principal difference between Jefferson's position and Hamilton's, so far as I can see, is that Jefferson would restrict the "implied" powers to those "without which... these powers [i.e. the enumerated ones] could not be carried into effect." (That restriction is in itself exceedingly vague, in my opinion.) Hamilton would give Congress a bit more leeway in determining its means. I think this points out one of the problems inherent in the Constitution, which serves to illustrate why it, by itself, is wholly inadequate to institute a limited government.

The second thing that I would like to take note of concerns the Louisiana Purchase. After he became President, Jefferson purchased the Louisiana territory from France. That purchase, regarded by many (including, perhaps, Jefferson himself) as the most important achievement of the Jefferson presidency, was made possible through the use of credit from the very national bank whose creation Jefferson himself had opposed but a few years earlier. If nothing else, this illustrates how difficult it is to live by one's principles in the real world.