The Evil of the "Living Document" doctrine

Being the son of an immigrant, I was taught at a early age that the founding fathers desired a country that was founded on the principles of Life, Liberty, and the pursuit of happiness.
I’ve come to realize that these unalienable Rights were not given to us by politicians nor by even the Declaration, but are natural, obtained by our existence, by our very birth and being. The fathers of this country believed that it was the government's duty to protect these rights for us against anyone or group that wished to take them away. They also mistrusted men of power, those, who charged with the projection of our rights, could become drunk with power, abuse their positions, and become the very people that they were to project our rights from. It’s one reason why they met and forged the U S Constitution. As Thomas Jefferson stated "Bind him down from mischief with the chains of the Constitution."
For sometime now certain groups and even members of the three branches of government have said this document is a "living document", who's meaning can be changed to fit the needs, wants, demands, and even ideology of society at large. If this is true then what protects the principles that our Founding Fathers were willing to be hung for? They are no longer rights secured and protected by the Constitution, but privileges granted to us by the courts and the whims of the populace, which they have the power to take away.
Those who feel that it is a living document argue and point to the preamble and section 8 of the Constitution and say "Look, General Welfare", to justify a myriad of laws, regulations, and even unfunded mandates. What about the Bill of Rights, the Tenth Amendment, "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." , and what it's main author, James Madison, a Federalist, said about it in Federalist paper #45. "The powers delegated by the Constitution to the Federal Government, are few and defined. Those which are to remain in the State Government are numerous and indefinite...The former will exercise principally on external objects, as war...The powers reserved to the several States will extend to all the objects...lives, liberties and properties...."
The convenience of the "Living Document" gives us gifts like the Patriot Act. It allows Congress to abandon their power to declare war and then lay it before the feet of a President. The most frightening, the branch that is supposedly to hold the legislatives leash, the Supreme Court, has decided, that cancer victim's using marijuana, grown in their own home, fall under inter-state commerce, not because it was transported across state lines but because it "could be". Could Grandma's garden be next, or will the State decide to give her land to Wal-Mart or some politically connected developer, like what happened to homeowners in New London. The Supreme Court has ruled that your liberties and property rights are out weighed by the desire to generate more tax revenue.
Alexander Hamilton feared a democracy leading to politicians catering to the masses at the expense of the individual, Thomas Jefferson feared a strong central government catering to the wealthy and business would do the same, both fears are now reality.