How the Senate works until the Georgia runoff elections results are clear

Short version: Republicans maintain the majority unless Democrats win both Georgia Senate seats. They currently have 51 Senators. That number could increase by one, stay the same, or decrease by one.

“The quirk that affects the initial Senate majority, though, is that Loeffler [is] a senator to start the new Congress, while Perdue“ is not.

Long version: AP explainer