The strongest argument I have seen on the subject of eliminating the Senate is the statistical one: a voter (or for that matter a sheep) in Wyoming has the congressional power of 70 Californians. Senators representing 40% of the states and no more than 18% of the total population (not including DC and Puerto Rico) have the power to prevent the senate from doing anything, and legislation can be passed by 60 senators who may represent as few as one-third of the total electorate. The small states probably have enough interests in common to warrant setting up a small-state caucus. But the small-state caucus should not have the power to run the country.
The original intent of the Framers may or may not have been the protection of wealth and privilege, but it was clearly born out of a compromise between states that perceived themselves as sovereign nations and wanted above all to protect their sovereignty. Absent such protection, the Constitution probably would never have happened at all, and the United States of America would probably have long since gone the way of the United Arab Republic and the Union of Soviet Socialist Republics.
But the intent of the Framers doesn’t have much to do with the way Congress looks today. For instance, the House of Representatives was assigned two-year terms to keep them accountable to the will of their local constituents. Today, however, many representatives spent more time in Congress than most senators, and they keep getting re-elected with little difficulty.
The Framers also originally intended the House of Representatives to represent the interests of their local constituencies, and the Senate to represent the interests of the country as a whole. That system fell apart well before the Civil War, mostly over issues of tariffs and trade with their differential impact on the North and the South. Today we take it for granted that senators will represent the interests of the primary industry or business of their respective states.
And, of course, the cities do not figure in the equation at all. There are 38 states with smaller populations than New York City, and 26 smaller than Los Angeles. Each of those states gets two senators and at least one congresscritter. The cities get precisely none. Most states are cobbled together from one or two large cities and their environs plus a “downstate” or “upstate.” Senators, generally, get to be senators by juggling the interests of cities and downstates, and only the congresscritters from the cities get to represent interests of those cities, in which the largest number of Americans live.
The depopulation of the “heartland” is a problem worthy of national attention in its own right. We may want to reverse it, or, given the shrinking water supply in those states, to encourage it. But we should at the very least be talking about it in the national legislative forum. That discussion is not going to happen any time soon, because it is in the best interest of those who represent the Plains states to keep their constituencies small. It makes campaigning cheaper and re-election easier.
While the size of the senate is constitutionally limited to two senators per state, the size of the House of Representatives has no constitutional limit at all. It is supposed to fluctuate with the decennial census. But it was capped at 435 by the Reapportionment Act of 1929 (!!!), and has not been increased since. This means that the House is now almost as mis-proportioned as the Senate, and completely out of proportion to what the Framers had in mind. The original argument on the subject in the 1780s was between 30,000 and 40,000 citizens per representative. Today, the average number of constituents per congresscritter is upwards of 600,000, though of course it varies somewhat from state to state.
Of course, the size of congressional delegations dictates the distribution of the Electoral College. Which means that a voter from a small state has more say in electing our president than, say, a New Yorker. Again, I do not mean to imply that the denizens of Wyoming and Vermont are elitists and oligarchs bent on protecting their riches and privileges. But they have been handed a dominant role in the governing of their country on a silver platter, and they cannot be blamed for accepting it.
So okay, the current structure of the legislative branch of the United States government needs revision. Doing it would require a constitutional convention during which all kinds of other mischief could happen, up to and including a civil war. Such mischief may be a bit less likely if we talk about the issues in terms of statistical fairness rather than the privileges of oligarchical elites. The alternative would be continuing the current system until both houses maneuver themselves into total paralysis, and fall into totally ceremonial roles not unlike those of the Roman Senate after the end of the Republic. At the moment, that’s starting to look like a real possiblity.