The Senate as now constituted is not as the Founders set it up. With passage of the 17th Amendment, States were required to popularly elect their Senators, rather than have them chosen by their states' legislatures, as was done until 1914.
What has developed is collection of multi-millionaires who have become so at taxpayers expense and are self-perpetuating based on the funds spent to re-elect them. They are much harder to remove without the oversight of the state legislatures.
This amendment also removed a key power of the sovereign states. If a state legislator with a two-year term hears from his constituents, who are few in number and hold his career in their hands, he is much more apt to discipline a Senator who acts against the interests of the citizens of a sovereign state.
Today's Republican Senators act directly against the wishes of their constituents on many issues. The way to bring these dogs to heel is to hold a Constitutional Convention of the States, as described in the constitution itself.
If Senators were elected by their legislatures, as they should be, there would immediately be a more conservative Senate. That's because even the worst Liberal states tend to have at least some conservative legislators,i.e. those usually elected from more rural rather than the urban districts populated by state-dependent minority voters. Case in point: New York State.
The Founders saw the Senate as a more mature, more conservative deliberative body, designed to hold in check any excesses engendered by a radical House!
One effect the old system had was turning state legislature races into little more than referenda on senate candidates. Remember the Lincoln-Douglas debates, in which the two men campaigned up and down Illinois for the senate seat. People weren't voting for state legislators on the basis of state issues--they were voting for electors for senator who incidentally would hold state legislature seats.
Finally, a series of scandals demonstrated that it was pretty easy to buy a senate seat when you only had to bribe a few state legislators.