Most people don’t realize that the Constitution has weasel words; but yes, the lawyers who drafted the document could be just a weaselly as current lawyers. From Eric Peters at ericpetersautos.com:

Why do we have unlimited government? Probably because the document that was supposed to limit it has done the opposite.
People were told the federal government could do no more than was specified – as in clearly described – by the Constitution, which supposedly enumerated its powers and left those not specifically enumerated to the states and the people (via the 10th Amendment to the Constitution).
So why does the federal government have power over essentially everything? Including over such things as how much gas the vehicles we’re allowed to buy may use? The answer is because the Constitution endowed the federal government with unlimited powers, without enumerating them.
But how did it do that?
Via the wording of the Constitution. Including words with open-ended definitions designed to be amendable to parsing in such a way as to countenance any power those in power (or grasping after it) wished to assert.
Wording such as “general welfare” – and “necessary and proper.” By incorporating such words – which can mean almost anything as they are matters of opinion – the lawyers who wrote the Constitution assured the federal government would assume unlimited power. It took time, of course. But that was always the point as it was necessary to engineer a gradual increase in the power wielded by the federal government for the same reason it is necessary to place the frog in a pot of cool water before gradually turning up the heat.

The Constitution is a political document. Essentially, it is a “Robert’s Rules of Order” for governance.
Jefferson’s unprecedented Declaration, however, is a moral document. The phrase “endowed by their creator with certain unalienable RIGHTS, among which are life, liberty, and the pursuit of happiness,” were intended as statements of moral ideals.
The word “rights” appears nowhere in the body of the Constitution. It appears only in its first ten Amendments. An “afterthought” thought necessary to assure ratification by nine of the 13 colonies.
However, the words you DO find in the Constitution are, as you indicate Eric, “general welfare” and “necessary and proper.”
And thereby, these two distinctly separate documents thought to represent the “new” ideals upon which the American “experiment” in government was founded, explain what has happened to America!
What were accepted to be proper moral ideals – prior, during, and after America’s founding, were put into conflict with what Jefferson penned regarding the individual rights of a human being.
Terms that claim “a greater good” than those set into logical motion through the individual responsibility and rights of the individual, have trumped Jefferson’s moral ideals from day one. They will continue to do so unless or until Mankind embraces the rights of the individual as morally/politically superior to moral collectivism – in any of its ugly incarnations.
To the extent a society reflects individual responsibility and the rights necessary to uphold it/them, the society is highly “moral.” To the extent it reflects the “necessary and proper” SACRIFICE of individual responsibility and rights on the altar of the “general welfare”- up to and including HUMAN sacrifice itself, it is evil – except for the “general welfare” of the collectors of sacrifice(s)!
Vote accordingly.
Dave