Retired Marine Colonel Lee Busby will launch a write-in campaign for the Alabama Senate seat, challenging Roy Moore, whose campaign has been mired in controversy since sexual assault allegations against him surfaced in early November.

The big picture: The election is on Dec. 12, and Busby has next to no chance of winning, but with many prominent Republicans distancing themselves from Moore, there has been speculation about a write-in candidate that voters who don't approve of Moore but don't want to vote Democratic could support.