Photograph of Mitch McConnell by Manuel Balce Ceneta/AP.

Just in case you haven't had enough bad news, here's a bit more from the domestic-politics desk. With less than a hundred days until the midterm elections, the Republicans now have a very realistic chance of retaking the Senate, which would leave them in over-all control of Capitol Hill for the next two years. (Virtually all the pundits reckon that it is a foregone conclusion that the Republicans will also maintain their majority in the House of Representatives.)

It's not by any means a slam dunk, but in a number of key states the opinion polls have recently moved in the G.O.P.'s direction. For what they are worth, the statistical forecasting models agree that a Republican majority is now the most likely outcome. To win control, the party needs to pick up six seats, and, as of now, it has a number of ways to get there.

Election Lab, a model operated by the Washington Post 's Monkey Cage blog, puts the probability of a G.O.P. takeover at eight-two per cent. Leo, the model constructed by the Upshot team at the Times, is less definitive, but it puts the chances of a new Republican majority at fifty-three per cent.

As I explained a while back in a quick bluffer's guide to the midterms, a dozen battleground states will determine the outcome, and that map strongly favors the Republicans. Seven of the states—Alaska, Arkansas, Louisiana, Montana, North Carolina, South Dakota, and West Virginia—voted for Mitt Romney in 2012. In addition, the Democrats are facing serious challenges in Iowa and Michigan, where two popular senators—Tom Harkin and Carl Levin—are retiring, and in Colorado, where Senator Mark Udall is up for reëlection. The only states where the Democrats have a decent chance of picking up seats from the Republicans are Georgia and Kentucky, but, in both places, despite the best efforts of two engaging young candidates—Michelle Nunn and Alison Lundergan Grimes—the Republican businessman David Perdue and Senate Minority Leader Mitch McConnell both hold narrow leads in the polls. These are traditionally Republican states, where President Obama is very unpopular among white voters.

Right now, it seems highly likely that the Republicans will win Montana, South Dakota, and West Virginia: in all three states, the Republican candidates are well ahead in the polls. (According to the Real Clear Politics poll of polls, the G.O.P. lead is fourteen percentage points in Montana, fifteen points in South Dakota, and nine points in West Virginia.)

As always, questions can be raised about the reliability of the polls, and there's more than three months to go until Election Day. Anything could happen. But if these races stay the way they are now, and many political pros think that they will, that would leave the G.O.P. needing just three* more pickups to gain a majority. To avoid becoming the minority party, the Democrats would have to win five of the seven* other tight races: Alaska, Arkansas, Colorado, Iowa, Louisiana, Michigan, and North Carolina. Such an outcome isn't out of the question. From here, though, it would be a mighty accomplishment on the part of the party, its donors, and the individual candidates.

The Democrats will be looking to hold on to Colorado, where Udall is facing a strong challenger in Cory Gardner, a conservative U.S. congressman, and Michigan, where Gary Peters, a Democratic congressman from the Detroit suburbs, is up against Terri Lynn Land, a former Secretary of State for Michigan. At this juncture, the polls suggest that Udall and Peters are both slightly ahead. The race in Iowa, by contrast, is virtually deadlocked. On the Republican side, it features the gun-toting, hog-castrating Joni Ernst, whose campaign slogan is "Mother. Soldier. Independent Leader." The Democratic candidate is Bruce Braley, a U.S. congressman from the district that includes Cedar Rapids and Dubuque. Ultimately, Braley's experience may win out, but, so far, suggestions that Ernst's candidacy would implode have proved unfounded. (Earlier this week, she resumed her campaign after taking two weeks off for National Guard duty.)

The contests in Alaska, Arkansas, Louisiana, and North Carolina are all ding-dong ones, too—with outside money and activists from both parties pouring in to help. In Alaska and North Carolina, the polls show the Democratic candidates slightly ahead. In Arkansas and Louisiana, the Republicans hold a slight edge. But each of these races has its own dynamic, and is tough to call.

In Alaska, Mark Begich, the incumbent senator, was elected by just five thousand votes in 2008. Fortunately for him, the Republicans are divided, and the G.O.P. primary isn't until August 19th. It pits a former attorney general of the state, Dan Sullivan, against the current lieutenant governor, Mead Treadwell. (Joe Miller, a Tea Party favorite who has the support Sarah Palin, appears to be languishing in the polls.) Still, Begich faces a hostile environment for Democrats. President Obama is so widely disliked in Alaska that Begich has been positioning himself as a check on the Oval Office. "I'll be a thorn in his butt," he told the Washington Post recently. “There’s times when I’m a total thorn, you know, and he doesn’t appreciate it.”

In Arkansas, where Obama is equally unpopular, senator Mark Pryor faces perhaps the toughest challenge of all the Democratic incumbents. His opponent, Tom Cotton, is a lean and hungry young U.S. congressman who attended Harvard Law School and served in the U.S. Army. Since winning the Republican primary in May, the thirty-seven-year-old has been busy portraying Pryor as a supporter of the President and a champion of Obamacare. That isn't necessarily wholly accurate, but it seems to be working. Five polls in a row have shown him ahead of Pryor, with an average lead of about four points.

Mary Landrieu, the three-term Democratic senator from Louisiana, is used to defying predictions of her demise. But in Bill Cassidy (no relation), a physician who serves as the U.S. congressman for the state's sixth district, which includes Baton Rouge, she is perhaps facing her most serious challenge to date. Flush with campaign cash, Cassidy has snatched a small lead in the polls, but Landrieu isn't done yet. Last week, the Times columnist Joe Nocera reported that she was about to land a key endorsement from the U.S. Chamber of Commerce, which is reportedly keen to secure her support to preserve the Export-Import Bank, which provided cheap financing to large corporations, and which conservative Republicans in Congress want to eliminate. If Landrieu can combine support from the business community with a big turnout from the state's black voters, she might just pull it off.

That leaves North Carolina, where minority turnout will also be key. Senator Kay Hagan is facing Thom Tillis, the speaker of the state assembly. In today's Republican Party, Tillis is what passes for a moderate: in May's G.O.P. primary, he comfortably fended off a challenge by the Tea Party. Since then, most of the polls have shown Hagan retaining a narrow lead, but a recent CBS/New York Times/YouGov survey showed that Tillis had taken a one point lead. Both candidates are raising buckets of money, and outside groups have been saturating the airwaves with negative ads. Tillis's side claims that Hagan has acted as a liberal rubber stamp for President Obama. Hagan's campaign is busy portraying her as a moderate, while depicting Tillis as a tool of the Koch brothers, who have contributed heavily to his campaign and financed a lot of anti-Hagan ads.

As Hagan showed in 2008, when she defeated Elizabeth Dole, she's a savvy campaigner. Given the advantages of incumbency and the fact that Tillis hails from a state legislature that is about as unpopular as the U.S. Congress, she must still be favored to win. But the problem for Democrats is that that might not be enough to save their majority. Even if Hagan and Landrieu both win, the G.O.P. could snatch control by taking Alaska, Arkansas, or Iowa*.

See, I told you this post was likely to depress you.

*Correction: An earlier version of this post involved an arithmetic error regarding the balance of seats.