One popular idea making the rounds among some conservatives and Tea Partiers is a call for the repeal of the 17th Amendment. From the LA Times:
A common theme among those in the "tea party" movement is that ordinary citizens ought to participate more in the business of government. Yet some tea party activists — and likeminded politicians and commentators — are espousing a return to the election of U.S. senators by state legislatures rather than the people. That would require repealing the 17th Amendment, which was ratified in 1913.
The "Repeal the 17th" campaign is rooted in a nostalgia for an era in which state governments exercised as much influence as the federal government — or more.
There's a lot of truth to the argument that the enactment of the 17th Amendment undermined federalism. State legislatures have a greater institutional incentive to protect federalism than do the people of a state. The people of a state may want to expand federal program spending in order to get their share of tax revenues, even at the expense of greater national power over issues reserved to the states. Although they are also elected by the people, state legislators have more of an incentive to protect the original distribution of powers between the national and state governments.
Here is what James Madison had to say about the matter (during congressional discussion of the Bill of Rights in 1789):
[T]he State Legislatures will jealously and closely watch the operations of this Government, and be able to resist with more effect every assumption of power, than any other power on earth can do; and the greatest opponents to a Federal Government admit the State Legislatures to be sure guardians of the people's liberty
The Seventeenth Amendment weakened the states' ability to resist the expansion of federal powers. The problem is that there is no point to trying to fix this problem -- an effort to amend the Constitution will be fruitless. It requires two-thirds of the Congress and three-quarters of the states. The tea-partiers would be well advised to devote their efforts to achieving significant limits on the federal government -- such as limiting federal spending, cutting taxes, and reversing Obamacare -- that don't demand an amendment to the Constitution. They will have a limited political window to apply their political capital; constitutional amendments will only waste it.