There is one extremely good reason that political junkies are focused more on elections this fall for the U.S. House of Representatives than for the U.S. Senate: A Democratic takeover of the House is significantly more feasible. If the president’s approval rating stays below 50 percent going into November (a pretty good bet), then the GOP will be in a situation where historically they have lost an average of 36 House races — 13 more than they’d need to flip the House this year.
Meanwhile, thanks to the sometimes strange effects of Senate “classes” (one-third of the chamber is up for reelection every two years), the 2018 Senate landscape is one of the worst for Democrats in living memory. That’s because they are defending an abnormally high number of seats (26 of the 35 up this year), and also because 10 of them are in states carried by Donald Trump in 2016 (with only one GOP seat in a state carried by Hillary Clinton). So posting the net gain of two seats needed to regain the Senate would involve either a Democratic “wave” large enough to swamp many red states, or the kind of inside straight Trump pulled off in 2016 by winning nearly all the close states. This statistic from David Wasserman nicely illustrates the lopsided odds in the Senate:
But let’s say for the sake of argument that a Democratic Senate might actually happen this November. As Jeff Greenfield notes at Politico, it would be a very, very big deal:
[I]f the [Democratic] goal is to thwart the wholesale, radical changes in policy that President Donald Trump’s administration is pursuing, the House is the wrong target. It’s the Senate that has been the most significant political player of the past four years. Although the president has made himself the obsessive focus of friends and foes, it was the Republican capture and retention of the Senate in 2014 and 2016 that was and is the key to what Trump has wrought.
As Greenfield observes, there’s really nothing a Democratic Senate couldn’t achieve that a Democratic House could, other than initiating impeachment. The Senate has broad investigative and oversight powers, and can certainly cast a big spotlight on various unsavory aspects of the Trump administration. But without a Republican Senate, Trump would lose an awful lot of power. Most notably, with Chuck Schumer replacing Mitch McConnell, he’d really struggle to get quick — or in many cases, even slow — confirmation of judges and of the more controversial Executive branch appointees.
Most importantly, the prospect that has provided the real glue between Trump and otherwise skeptical “movement conservatives” and Evangelical leaders — a fundamental revision of constitutional law via the Supreme Court — would quickly fade. It is now very unlikely that a SCOTUS retirement can occur in time to give Trump and the GOP Senate the time to fill a seat before the midterms. So the great right-wing hope that Anthony Kennedy or Ruth Bader Ginsburg will give way to that fifth conservative Justice willing to overturn or significantly revise Roe v. Wade will have to be deferred until 2019 — or later if Republicans lose the Senate this year. And if Trump took the blame for that happening, his support level in key parts of his base might well decline.
On the other hand, imagine that Republicans continue to narrowly hang onto the Senate this November. The possibility of losing the upper chamber in 2020 will hang over the presidential election of that year as well. Depending on what happens in two special elections this year (in Minnesota and Mississippi), Republicans will probably be defending 21 of 33 seats. Yes, all but two will be in states Trump carried in 2016 (the exceptions being Colorado and Maine), but the size of the battleground means that Democrats will have a good chance to win both the presidency and the Senate in what will after all be a more Democratic-leaning presidential electorate. And should Trump again somehow win the White House while losing the Senate, he would be the lamest of lame ducks, unable to get his second-term Cabinet easily confirmed, and blocked from any big game-changing judicial appointments as well.
So it doesn’t just matter whether Republicans maintain control of the Senate this November. Their margin of control will set the 2020 table for good or for ill. And if they lose the Senate altogether in 2018, Trump may find the second half of his first term to be an unfulfilling experience that he does not want to extend.