The argument for repealing the Seventeenth Amendment must be taken up.
Since the direct election of Senators was initiated by Progressives looking to tap into populist power, the Senate has witnessed a growing chaos of membership, in which Senators outside of the cultural and political norm of entire states have won elections in a bad year for the opposing party.
Virginia Senator Jim Webb rose to power only because 2006 was a bad year for Republicans, including the incumbent George Allen, who following some nasty missteps and faux pas, faced the wrath of a petty press.
The Senate makes decisions which affect the entire country. These members should not be elected directly by the voters, but by the more stable and politically inclined legislatures.
The Framers of the Constitution created a form of government which discouraged power being concentrated in the hands of any one group, including the masses of individual voters. The Senate was the chamber which would protect the interests of the several states, which in many cases differs greatly from the will of the people or the ambitions of the federal government.
The proper check on populist sentiment and federal encroachment is a chamber whose members respond to the states themselves, represented by the legislatures of each state.