The Constitution originally endowed the Federal government with specific legislative jurisdiction. The Federal government was not permitted to legislate regarding most areas, as most areas were seen to be the sole jurisdiction of the states. However, now there are few areas where the Federal government is NOT involved.
Medicare and Social Security, for example. There is no Constitutional backing for them.
These welfare programs are now allowed by the Supreme Court because of an incorrect interpretation of the Welfare Clause. This clause says,
"The Congress shall have power to lay and collect Taxes, Duties, Imposts, and Excises, to pay the Debts and provide for the common Defense and general Welfare of the United States."
Today, ever since United States v. Butler, the General Welfare clause has been interpreted as giving Congress power to spend for purposes outside of its Constitutional boundaries. In other words, Congress can do what it wants as long as it's for "the general welfare."
The Founders disagreed on what exactly the Welfare Clause meant, but none would have supported such a sweeping delegation of power. In fact, as James Madison pointed out, if the GWC really meant that, then the rest of the Constitutional limits, delegating specific powers to Congress and specific powers to the states, were meaningless. And indeed, such has become our current state of affairs. The government is involved in schooling, gun laws, medical insurance, religious liberty (or repression), and the list goes on.
We would not have Medicare, Obamacare, Social Security, and most of all the federal policies currently enacted, if the Supreme Court had got this right and ruled that the GWC does not give Congress generally unlimited power, but only allows Congress to do what is a) sanctioned elsewhere in the Constitution, or b) the states cannot do (such as NASA). This was the view of Alexander Hamilton, and is as far as the Founders went in the direction of our current state.
Bottom line: The SC has caused a TON of trouble. All these entitlement programs are heaping up debt that future generations (such as me) will have to pay for.
The Federal government was never meant to be so big.