From “Why Republicans Are Favored To Win The House, But Not The Senate” by Nate Silver at FiveThirtyEight:
Republicans are substantial favorites to take over the U.S. House of Representatives following this November’s midterm elections, but the U.S. Senate is much more competitive, according to FiveThirtyEight’s 2022 midterm election forecast, which launched today….
Democratic hopes of keeping the Senate are much more viable, however. Part of this, as I mentioned, is because they appear to have stronger candidates in a handful of key races. Pennsylvania, for instance — which is an open seat after the retirement of Republican Sen. Pat Toomey — is ordinarily the sort of seat that you’d expect Republicans to win since Pennsylvania is a purple state in a Republican year. However, the Democratic candidate, Lt. Gov. John Fetterman, is ahead of Republican Mehmet Oz, the doctor and TV personality, in every poll conducted so far. The model, though, is trained to be a bit skeptical given the fundamentals of the race, so it hedges against those polls and, at this point, has determined that Pennsylvania is best thought of as a toss-up. Still, that means Democrats have roughly a 50-50 chance of gaining a GOP-held Senate seat, offsetting potential losses elsewhere.
Indeed, our forecast sees the overall Senate landscape to be about as competitive as it gets. The Deluxe forecast literally has Senate control as a 50-50 tossup. The Classic and Lite forecasts show Democrats as very slight favorites to keep the Senate, meanwhile, with a 59 and a 62 percent chance, respectively.
Part of this is because Senate terms last for six years, and so most of these seats were last contested in 2016,3 a mediocre year for Democrats in which they lost the popular vote for the House and also lost Senate races in swing states such as Pennsylvania, Wisconsin and Arizona. Of the 35 Senate seats up for grabs in November, 21 are currently held by Republicans. True, most of these are not competitive, but in addition to their chances to gain a GOP-held seat in Pennsylvania, Democrats also have credible chances in Wisconsin and North Carolina (and outside chances in Ohio and Florida, although those are a stretch given how GOP-leaning both states have become).
Republicans don’t have any surefire pickups, meanwhile. Our model regards their best chances as being in Georgia, but that race is rated as a toss-up. And the races in Arizona and New Hampshire merely lean toward the Democratic incumbent, meaning they are still highly plausible GOP pickup opportunities.
Still, the picture isn’t as bad as you might expect for Democrats. If the political environment really deteriorates for them, they’ll be in trouble, lose most of the competitive races and even blue states like Colorado could come into play. But if things are merely pretty bad for Democrats instead of catastrophic, the outcome of the Senate will remain uncertain enough that stronger candidates could make the difference for them.
The pundit prognosis for the House, Governorships and state legislatures is still pretty bad for Democrats. But recent Supreme Court decisions on abortion, guns and school prayer underscore the importance of having a Democratic majority in the senate to prevent the high court from getting even worse. Democratic strategists face some tough choices about where to allocate resources in this cycle. But investing more in holding the Senate majority looks like a wiser option.