Republicans appear set to win a narrow majority in the House based on preliminary results, but control of the Senate remains completely up-for-grabs with three races yet to be called. Control of the Senate could come down to a runoff election in Georgia if neither party can win both Arizona and Nevada, two states still counting ballots in races too close to call.
The Senate race in Georgia is slated to head to a special runoff election in December because no candidate secured a majority of the vote as required by state law.
"What you have right now is two candidates who have somewhere around 49 or a little bit more percent of the vote, but neither one of them has 50%. And there may be some very minor candidates who would get a few votes," Black said. "If the state of Georgia remains undecided, then we might not know who will win control of the Senate for quite some time."
The other races that are undecided, Arizona and Nevada, Black said should be decided fairly soon.
"It's unclear who will control the Senate. It looks fairly evenly split still... There's still a lot of uncertainty at this point. And because the Senate has so much influence over foreign policy, the outcome of that is going to be important," he added.
Commenting on the projections for the House of Representatives, Black said it is "still a little bit in doubt, but it's leaning towards the Republicans."
"But by far, far smaller margin than we had expected," he added. "We thought we [Republicans] would pick up perhaps 30 seats in the House. And it's going to be very narrow. The most recent numbers that I've seen shows that the Democrats have 215 seats. The Republicans have 220, And then there are still other things still to be sorted out, but right now, it looks like the Republicans will win control of the House, but it's not 100% certain."
As of early Wednesday afternoon, NBC News projects the Republicans to win 222 seats in the US House of Representatives while Democrats are expected to win 213 seats in the next term of Congress. 218 seats are required to win the majority. However, these numbers are subject to change as some final results are yet to be confirmed.