Georgia: Why does the state have a runoff election for Senate?

With both Senate contests in Georgia falling below a 50 per cent majority,  the state is headed for two run-off elections.

In the regular election, Republican incumbent David Perdue is facing a challenge from Democrat Jon Ossoff. In the special election, GOP appointee Kelly Loeffler is defending her seat against Democrat Rev Raphael Warnock.

But what is a run-off election and what impact will it have?

What is a runoff election?

State election officials declare a runoff election when no candidate in a given contest earns enough votes to clear the state-mandated percentage share of the vote to be victorious.

Read more: Latest Georgia Senate runoff election odds

In most cases, the two candidates who earned the largest share of votes advance to a head-to-head runoff so that one is guaranteed to earn at least 50 per cent plus one vote. Because the US Constitution leaves it up to individual states how to run their elections, they have varying thresholds to declare an outright winner.

What is happening in Georgia?

The state of Georgia has a majority-vote requirement, which means a candidate must secure at least 50 per cent of the vote in order to win the election. If 50 per cent of the vote is not secured, a runoff will be held.

This year, the state is unusually holding two races for senate as the seat for former Senator Johnny Isakson, who retired last year, also needs to be filled.

In the regular election, Sen Perdue fell just under 50 per cent of the vote needed for a majority against Democratic challenger Jon Ossoff with 49.7 per cent to 47.9 per cent with 99 per cent of the vote counted, and a runoff was declared by the Associated Press on Saturday.

Read more: When will we know the Georgia Senate runoff election results?

In the special election, Sen Loeffler came in second behind Democrat Raphael Warnock with 25.9 per cent to 32.9 per cent. The runoff was called when it became evident neither candidate would reach the 50 per cent majority-vote requirement.

When will the run-off happen?

The runoff elections are slated to take place in Georgia on 5 January, 2021.

With both seats left open until a January runoff the Senate in a precarious position with neither party having a clear majority when it reconvenes next year.

Why is this important?

The two runoff elections could lead to an especially contentious and crucial battle for control of the Senate, determining which party holds power.

With Joe Biden having been declared the winner of the presidential race, Democrats need a net gain of three seats to win control of the Senate. 

Currently, Democrats have a net gain of one seat in the US Senate in this year's election. In the case that Democrats manage to secure two more seats vice president, Kamala Harris would have a deciding vote whenever there is a 50-50 tie.

Therefore, If the predicted electoral map remains as it is, Democrats could hypothetically retake Senate control by securing the two extra seats in the January election.

A runoff election would also widen the electorate in the state as those who are currently 17 years old but turn 18 by January will have the opportunity to participate, which could have a chance of altering the vote.