[T]he Senate is as much a product of bare-knuckled, self-interested politics as last week's fight over military earmarks. In Philadelphia in 1787, the smaller states favored the New Jersey Plan -- one chamber with equal representation per state -- while James Madison argued for two chambers, both apportioned by population, which would benefit his Virginia.The delegates finally settled on the Connecticut Compromise, or the Great Compromise. Seats in the lower chamber would be apportioned by population (with some residents counting more than others, of course) while seats in the upper chamber would be awarded two per state.
The idea was to safeguard states' rights at a time when the former colonies were still trying to get used to this new country of theirs. But the big/small divide was nothing like what we have today. Virginia, the biggest of the original 13 states, had 538,000 people in 1780, or 12 times as many people as the smallest state, Delaware.
Today, California is 70 times as large as the smallest state, Wyoming, whose population of 533,000 is smaller than that of the average congressional district, and, yes, smaller than that of Washington D.C., which has zero votes in Congress to Wyoming's three. The 10 largest states are home to more than half the people in the country, yet have only a fifth of the votes in the Senate.
[...]
For the first few decades in Congress's history, the more democratic House was where the action was. "The authors of the Constitution really thought the House would be the driving engine, and the Senate would just be the senior group that would perfect legislation that came up from the House," Ritchie said.But after the Missouri Compromise of 1820, it was clear that the battle over slavery would be fought in the upper chamber. After the Civil War, the Senate became the bastion of the GOP as the party pushed to admit pro-Republican states to the union. Nevada was admitted in 1864 to help ratify the Civil War amendments despite being virtually empty; the Dakotas joined in 1889, split in two to provide more votes in the Senate and the Electoral College; Wyoming joined a year later with 63,000 residents.
With these added votes in the Senate and the Electoral College, the Republicans dominated throughout the late 19th century despite Democratic strength in the House. High tariffs, land giveaways in the West, lax regulation of railroads and a pro-business Supreme Court were all thanks partly to the underpopulated new states, says MIT historian Charles Stewart III.
A few decades later, the politics had flipped, and it was the South relying on the Senate -- and the filibuster -- as a bulwark against civil rights legislation. In any case, the Senate's preeminence was established, even as the Britain's House of Lords and upper chambers in other countries' legislatures lost sway. Add the rise of the filibuster and the fact that small-state senators tend to stick around longer, gaining powerful chairmanships under the seniority system, and you've got today's change-resistant Senate.