Mitch McConnell has broken the Senate, and he's been aided by population changes that have made the Senate the most undemocratic it has ever been in history. GovTrack.us has crunched the numbers since 1789 and found the tipping point. It was 2017 when, "for the first time, the Senate’s decisions were often made by a coalition of states representing less than half of the country’s population."
Throughout the Senate's history, there was equilibrium; about 68 percent of senators voted for most legislation that passed, and they in turn represented about 68 percent of the population. In 2017 the median share of senators passing bills and confirming nominees dropped to 58 percent—the lowest in almost 90 years. More tellingly, for the first time ever in the Senate, a minority of the population ruled. Those senators represented just 49.5 percent of the U.S. population.
Part of this is population growth in Democratic states, meaning Democratic senators are representing millions more people than Republicans are. That's reflected in the massive popular-vote advantage Democrats had in the 2018 Senate races, a nearly 60-40 popular-vote win, even with a net loss of seats.
The end to the executive and judicial nominations filibuster under Democratic leadership was part of this, with McConnell shoving through nominees for so many positions that had been bottled up by Republican maneuvering under President Obama. McConnell's efforts to undo as many of Obama's actions as possible in that first year were also a factor. He used the Congressional Review Act to repeal Obama administration rules and regulations several dozen times—more than ever before. The CRA requires a simple-majority vote, and is not subject to the filibuster. So that significantly increased the number of bills the Senate considered, and the number passed with just Republican votes. It also decreased the median percentage of senators voting yes on legislation—just 54 percent, the lowest in the 30 years of available data. That 54 percent represented just 47 percent of the country—also the lowest in 30 years.
On confirmations, however, it's worth noting that because Democrats continued to follow the norms of the Senate after getting rid of the filibuster for all but Supreme Court nominees in 2013, confirmations still got 80 percent support, representing 85 percent of the population. That's because committee chairs, particularly then-Judiciary Chair Patrick Leahy, didn't plough over Republicans and honored their obstruction. Which helped a lot in the 2014 election.
With a newly Democratic House, the Senate won't have this glaringly undemocratic performance where legislation is concerned. That's not necessarily good, because under McConnell it will be doing the absolute minimum of legislative action possible. For example, watch McConnell refuse to bring any of the House bills to reopen government to the floor. And don't expect him to slow down the pace on nominations. With two more Republicans, the disparity on those votes will possibly increase.
It's minority rule. Full stop. Worse, it's Trump rule.