In 1913, the seventeenth amendment turned the Senate from a system where states chose how their senators were chosen, to one in which the entire senate was directly elected.

This is one of two major turn-around changes to the form of our representative government (the other being combining the posts of Vice President and President into a partnership).

It is extraordinarily hard to argue against such a change; in fact, when the change occurred some states already specified that their senators were directly elected. But what it meant was, instead of having one house representing federal needs and one representing state needs, we now had two houses each representing federal needs.

The only differences between senators and representatives became the number of voters electing them and the number of years between elections. The senate might take a few more years to do it, but both houses now needed to respond to hot-button popular issues rather than representing different interests. John Dean quotes James Madison:

James Madison was not only involved in structuring the system, but was also a keeper of its contemporaneous record. He explained in Federalist No. 10 the reason for bicameralism: “Before taking effect, legislation would have to be ratified by two independent power sources: the people's representatives in the House and the state legislatures’ agents in the Senate.”

The need for two powers to concur would, in turn, thwart the influence of special interests, and by satisfying two very different constituencies, would assure the enactment was for the greatest public good.

The system as designed by the Framers was in place for a century and a quarter, from 1789 until 1913, when the Seventeenth Amendment was adopted. As originally designed, the Framers' system both protected federalism and ensured that relatively few benefits would be provided to special interests.

This is all in response to a rising scholarly questioning of both the need and the desirability of the seventeenth amendment. George Mason University Law Professor (and Volokh Conspiracy blogger) Todd Zywicki has addressed the issue and has inspired a few further blogs such as Dean’s and Bruce Bartlett’s.

Bartlett writes about Zywicki:

As George Mason University law professor Todd Zywicki notes, prior to the 17th amendment, senators resisted delegating power to Washington in order to keep it at the state and local level. "As a result, the long term size of the federal government remained fairly stable during the pre-Seventeenth Amendment era," he wrote.

Zywicki also finds little evidence of corruption in the Senate that can be traced to the pre-1913 electoral system. By contrast, there is much evidence that the post-1913 system has been deeply corruptive.

In other words, the post-seventeenth amendment Senate has become more susceptible to special interests because it needs their money. Ironically, the directly-elected senate may be less responsive to the needs of its constituents because of this. For example, despite the high public approval for medical marijuana when doctors prescribe it, and despite state after state passing pro-patient laws, AIDS and cancer patients still risk jail if they use effective medicine.

And they risk jail precisely because even though their state has made their medicine legal, the federal government has the power to arrest them anyway. Decades with a loosened brake on federal restraint has, unsurprisingly, strengthened the federal government over state and local governments.

It seems extraordinarily unlikely that the 17^th amendment could be repealed, but it also seems worth considering.