(CNN) In four weeks, Alabama will go to the polls to elect a new US senator, but recent and mounting allegations of sexual misconduct by Republican nominee Roy Moore have thrown the contest into disarray, with top GOP officials in Washington calling on their party's candidate to step aside.

The seat is currently filled by Sen. Luther Strange, a Republican appointed by former Gov. Robert Bentley in February after Jeff Sessions left to become President Donald Trump's attorney general. Bentley is now out of the picture, having resigned in April under threat of impeachment. About a week after taking office, his successor, Gov. Kay Ivey, made the fateful decision to move up the special election, which Bentley had set for next November, to December 12 of this year.

When Strange, a relative moderate, lost the GOP primary to Moore, the twice-ousted former chief justice of the state supreme court, the race opened up -- a bit. But with Moore's campaign now riven by scandal, Democrat Doug Jones, a former federal prosecutor, is ticking up in the polls.

So, how does it all end? Here are the five most likely outcomes. (Disclaimer: Because it's 2017, and no one really knows anything, unsaid option #6 is probably your best bet. We're also waiting to hear from Trump, who could rewrite the narrative with a single tweet.)

1. Roy Moore wins, becomes Sen. Roy Moore (R)

For all the deeply troubling accusations against him, Moore remains the bookies' favorite to win next month.

Decades of political history suggest it will be exceedingly difficult for anyone with an R next to their name to lose this race. The last Democrat to win statewide in Alabama: Jim Folsom Jr., the son of a governor and former governor himself, who was voted lieutenant governor (for a third time) in 2006.

On the federal level, the most recent Democrat elected out of the state was Richard Shelby, who won his first term in 1986. He became a Republican in 1994. The last Democrat to both enter and leave the Senate as a Democrat was Howell Heflin, who retired in 1997. It's been more than four decades since the state delivered its electoral votes to a Democratic presidential candidate.

Point being: Moore and Jones themselves are only a part of the story here. And given the tribal nature of modern politics, it's unlikely a sizable number of Republican voters are poised to cross party lines to deliver this crucial seat to a Democrat.

Meanwhile, calls by "establishment" GOP officials in Washington -- both Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan have said Moore should stand down -- don't figure to carry much weight. If anything, the backlash from Congress, which is less popular than Moore, could galvanize his wobbly supporters.

But here's the caveat: some Republicans have said they would try to block Moore by other means. More on that below.

2. Doug Jones wins, becomes Sen. Doug Jones (D)

If Strange, recipient of a half-hearted endorsement by Trump, had survived the primary, we probably wouldn't be thinking much about this election, at least not 28 days out. But he didn't and now Jones, the wind at his back, has a legitimate shot to prevail in December -- especially if more alleged victims emerge and Moore continues to say things like, "I don't remember dating any girl without the permission of her mother," as he told Sean Hannity last week.

Jones' path to the Senate banks on two things: Democrats showing up to the polls in droves and (even a sliver of) Republicans sitting out.

Josh Moon, a columnist for the Alabama Political Reporter, told CNN on Friday that Moore's base of support was unwavering, "but what (the allegations) could do is push a few more Democrats to the polls, possibly get a few hesitant Republicans to crossover and keep more moderate Republicans at home. I think the last one is the big one. An Alabama moderate Republican is basically equal to a hardline Republican elsewhere in America."

3. Republicans launch write-in campaign for someone not named Roy Moore

As Sen. Lisa Murkowski knows, it can work. The Alaska Republican launched a successful write-in bid after losing her 2010 primary to tea party challenger Joe Miller, winning a second full term in the general election months later.

But Republicans in Alabama don't have a (previously elected) incumbent like Murkowski to bank on. And with the Senate divided so narrowly now between the parties, concerns that Alabama Republicans would split their votes between Moore and a write-in candidate, effectively handing over the seat to Jones, is a very real -- and probably decisive -- concern.

4. Roy Moore wins, gets expelled from the Senate by the Senate

Yes, the Senate can by law vote to expel one of its own. It's happened 15 times before , 14 of them as part of a Civil War-era purge of Confederate traitors and no-shows. But those are the most recent examples.

Other senators have been threatened with expulsion , but they either escaped the boot or resigned before it swung.

Moore, as we've seen over the last few days, is not bothered about his potential future colleagues' feelings. If he doesn't drop out now, it's hard to see him bailing once he's arrived. And an actual vote to expel, which requires a two-thirds majority, could do untold damage to the fragile Republican governing coalition.

5. Alabama Gov. Kay Ivey delays the race

Putting off the vote, a special election conducted at the governor's orders, could buy Republicans time to either remove Moore from the ticket or build up support for a credible write-in alternative. But like so many of the options being weighed by the GOP right now, it threatens to alienate Moore voters, a base of support they simply cannot lose if they want to hold on to the seat.

CORRECTION: A previous version of this story misstated Heflin's first name and the year he retired from the Senate.