If you are a civically engaged American who follows political news closely, you are probably aware that partisan control of the U.S. Senate hangs in the balance once again this November. If Democrats can regain the gavel after losing it two years ago, it could have a big impact on prospects for governing by either major-party presidential nominee. Right now the odds lean slightly in favor of a Democratic takeover, mainly because the Senate landscape is very, very favorable: 24 of the 34 seats up this year are currently held by Republicans, and 6 of them are in states carried twice by Barack Obama. Since Republicans now hold a 54–46 margin in the upper chamber, a gain of four net seats by Democrats will flip the Senate if Hillary Clinton is elected president and vice-president Tim Kaine holds the tie-breaker, with five seats needed if Mike Pence has the whip hand.
The dynamics of which party controls the White House, the Senate, and even the House will determine, as my colleague Jonathan Chait has explained, the fate of that great instrument of obstruction, the Senate filibuster. Virtually any change from the status quo will probably doom the disreputable minority-party veto.
But if the Senate does change hands in November, the odds are high that it will change hands again in 2018, and yet again in 2020. In 2018, the landscape turns bright red, with Democrats having to defend 25 of 33 seats at stake — 5 of them in states carried by Mitt Romney in 2012. The odds of a one-seat or two-seat Democratic majority surviving that landscape, particularly given the recent emergence of a significant Republican turnout advantage in midterms, and especially if there is a Democrat in the White House (midterms usually produce losses for the White House party), are very low.
But then in 2020, the color of the landscape changes yet again, with two-thirds of the seats (22 of 33) at stake being held by Republicans. The likelihood of Democrats regaining the gavel then are enhanced by the relatively strong turnout dynamics the Donkey Party enjoys these days in presidential elections.
So, add in the party control switch that occurred in 2014, and we have better-than-even odds that partisan control of the Senate could flip in four consecutive elections. That has not happened before.
To get very technical about it, the gavel did change four times in just two years from 2001 to 2003 thanks to some very quirky developments: The gap between Senate and presidential/vice-presidential inauguration dates meant that the 50-50 Senate produced by the 2000 elections was for 18 days controlled by the Democratic Party of outgoing veep and SCOTUS victim Al Gore, before he handed over control to incoming veep and SCOTUS beneficiary Dick Cheney. Then, less than six months later, Vermont Republican Jim Jeffords switched parties, flipping the Senate back to the Democrats, who proceeded to lose it all over again in the 2002 elections. Good times, eh?
It should all serve as a reminder that our constitutional system puts some very harsh constraints on the ability of popular majorities at any one time to produce a workable majority in Washington. First of all, of course, the Senate gives equal representation to California with its 39 million people and Wyoming with its 586,000. Second of all, the staggered system of Senate elections means that a popular tide in any one cycle can at most affect one-third of the seats. And third of all, the same system means exposure of any one party to popular censure in any one election is limited by the landscape for any one “class,” which alternates between presidential and midterm elections.
None of this mattered nearly so much back in the days when the two parties were ideologically diverse and cross-partisan governing coalitions were possible. At a time of partisan polarization and gridlock, however, and particularly if the filibuster goes the way of the dinosaur, the change in the governing landscape produced by a partisan “flip” could be large. And we could see it happen again and again. Not so good times, eh?
Indeed, the institution once known as “the world’s greatest deliberative body” is in danger of becoming a piñata batted around by the two major parties. It is reasonably clear that was not part of the founders’ design.
When will the flip-flopping end? That’s impossible to say, of course, but one contributing cause is the winning streak Democrats seem to be putting together in presidential elections (if Clinton wins, that will mean Democrats have won the popular vote in six of the last seven presidential elections), which produces regular midterm reactions favoring Republicans. It’s up to voters to break that pattern one way or the other.