On Monday afternoon, Sen. Thad Cochran, the first Republican in over a century to win a statewide race in Mississippi and the longest-serving member currently in Congress, announced he would resign from office on April 1. The news wasn’t unexpected — Cochran’s worsening health began stirring up rumors of resignation as early as last year — but it still throws a wrench into the 2018 midterm elections, and in particular, the U.S. Senate map.

That’s because Cochran’s seat wasn’t scheduled to be up for election until 2020, so we’re looking at another special Senate election in the Deep South. As you might recall, Democrats have had some success with those recently. Like Alabama, a Mississippi special election will be a steep uphill climb for Democrats, but like Alabama, the seat could fall into their hands under the right circumstances. Several things would need to go right for Democrats to snag Cochran’s seat — perhaps a bad Republican candidate and a bad Republican political environment — but the 2018 Senate map offers the party such slim pickings that even a reach like Mississippi opening up counts as a meaningful shift.

Here’s how everything will play out. Under Mississippi law, Republican Gov. Phil Bryant will appoint a new senator to take over for Cochran until a special election is held this November (concurrently with the regularly scheduled midterm elections). There is a catch, though: Special elections in Mississippi are nonpartisan; that is, party affiliations aren’t printed on the ballot, and — instead of party-specific primaries — all candidates will run in one free-for-all of a race. If no one gets a majority of the vote in the first round, the top two finishers will face off in a runoff election.

The nonpartisan setup has the potential to help Democrats, because Mississippi is two things: Very Republican and very inelastic, meaning it has very few persuadable voters and doesn’t swing much from one election to the next. Most voters in Mississippi reliably vote for either Republicans or Democrats. Under normal circumstances, that makes it extremely difficult for any Democrat to claw his or her way to 50 percent of the vote, but in a campaign without party labels (or at least where they aren’t front and center), the lead weight that is a “D” next to one’s name is partially lifted.

And Democrats have a couple of candidates on their bench who could credibly run a centrist campaign. Attorney General Jim Hood is the last Democrat to be elected statewide in Mississippi, and he has won all four of his attorney-general campaigns by at least 10 percentage points (and that was with the “D” next to his name — although it was also in state, not federal, elections). Hood says he’s interested in running for governor, but that election won’t occur until 2019, leaving his 2018 schedule fairly open. Public Service Commissioner Brandon Presley (apparently Elvis’s second cousin) was national Democrats’ top choice to run against Republican Sen. Roger Wicker for Mississippi’s other U.S. Senate seat (which was already scheduled to be on the 2018 ballot), but he turned them down in January. Maybe he’ll feel differently about running for a seat without a powerful incumbent.

As for who might run for Republicans, keep an eye on whomever Bryant appoints to the seat. Republicans reportedly want Bryant to appoint someone who will run in (and win) the special election, not just a caretaker. The term-limited Bryant has rebuffed advances from President Trump and Senate Majority Leader Mitch McConnell to appoint himself. Instead, Lt. Gov. Tate Reeves and Secretary of State Delbert Hosemann are rumored to be the frontrunners for the appointment. (However, Reeves is also reportedly interested in running for governor.)

The elephant in the room is Chris McDaniel, and not just because he’s a Republican. The deeply conservative state senator mounted a tea-party-flavored primary challenge against Cochran in 2014 and only barely lost, 51 to 49 percent. This year, he’s trying again, running against Wicker in the GOP primary. As of Monday night, McDaniel was saying that he intended to continue his campaign against Wicker rather than switch to Cochran’s open seat, but he also told Mississippi Today’s Adam Ganucheau that “you never want to foreclose options in politics.” Legally, there’s nothing stopping McDaniel from dropping out of the Wicker race and joining the open-seat field.

If McDaniel ran, and especially if a runoff election pitted him against a strong Democrat like Hood or Presley, you would see Democrats start to get excited about their chances in Mississippi. McDaniel has a long history of controversial statements: He has blamed hip-hop for gun violence, said movies should have more Muslim villains, spoken before pro-Confederate organizations, and dismissed Women’s Marchers as “unhappy liberal women.” More than one commentator has compared him to Roy Moore, the similarly inflammatory conservative who famously blew December’s special U.S. Senate election in Alabama for the GOP.

McDaniel is no Moore — the latter’s allegations of underage sexual misconduct set him in a class of his own — but Mississippi is also no Alabama. Whereas Trump won Alabama by 28 percentage points, he won Mississippi by only 18 points. In 2012, Mitt Romney defeated then-President Obama in Alabama by 22 points but only took Mississippi by 12. The Democratic Party’s floor in Mississippi is much higher than in Alabama — every Democratic presidential candidate since Al Gore has won 40 percent of the vote or more — thanks in large part to the largest African-American population (in terms of percentage) of any state (38 percent). All else being equal, we would expect Democrats to have an easier time winning Mississippi than Alabama.

The last time a pollster asked Mississippi voters to choose between McDaniel and a Democrat, the Democrat wasn’t too far behind. Granted, we only have a couple of polls, and they’re old (from the 2014 cycle), but that was also a much more Republican-friendly political environment than the current one.

Make no mistake: Mississippi is still a very red state, and its inelasticity means any Democrat will have to work twice as hard to persuade the few gettable voters available while still turning out the state’s sizable Democratic base. But Cochran’s seat becomes only the ninth Republican-held Senate seat to be on the ballot in 2018, most of them on dark red turf. Democrats must pick up at least two of them (and not lose any of their own) to take a Senate majority. Mississippi is a long shot, but it’s one more shot than Democrats had on Sunday.