The US Senate, with votes designated by state as opposed to population, was one of the most important and unfortunate compromises made when the Constitution was being written. Small states threatened to bolt if the US Senate was based upon population and the Southern states insisted that their non-voting slave populations be counted as well. This compromise was opposed not only by Madison, the principal author of the Constitution, it also was the first issue that caused the constitutional convention to almost fall apart entirely.
Here’s Madison: “In all cases where the general government is to act on the people, let the people be represented and the votes be proportional. . .” He argued the small states would be able to “extort measures” from the larger states and “frustrate the will of the majority.” Nice foresight.
“It seemed now to be pretty well understood that the real difference of interest lay, not between the large and small but between the northern and southern states.” Madison opposed the counting of votes of non-voting southern blacks on both moral and political grounds. (Excerpts from A People’s History of the Supreme Court)
Benjamin Franklin believed that a higher house elected by legislatures instead of the people was an inappropriate vestige of the aristocratic rule that the colonies were emerging from. He also variously proposed that we only have one house of congress, and that their representation be determined either by population or by the relative proportion of taxes paid into the federal government by the state. As an aside, he also proposed to the PA convention debating the Articles of Confederation that PA oppose great concentrations of wealth as (paraphrasing) antithetical to a Democratic society. (Info from Isaacson’s biography of Franklin.)
Interested in other examples of the pro-Democracy founders who opposed the clearly anti-democratic structure of the senate. That being said, we shouldn’t be surprised when the Senate votes against initiatives that are widely supported by the public. Thwarting the democratic will of the country? That’s just the Senate being the Senate.