WASHINGTON (NYTIMES) - As the dust settles from the presidential race, the eyes of the political world have already shifted to Georgia, where two run-off elections set for early January will almost certainly determine which party has control of the Senate.

The outcome of the contests, which will play out two weeks before President-elect Joe Biden's inauguration, will either swing the majority to Democrats, handing the new president broad power to carry out his policy agenda and push through nominations as he sees fit, or leave Republicans in charge, allowing them to influence his plans.

In the weeks ahead, tens of millions of dollars in campaign cash are expected to pour into the state to fund a marathon of political advertising, while party leaders and interest groups on both sides train their attention on the races.

Here's how it will work.

Q: What is a run-off election?

A: A run-off election is essentially a rematch that is held when none of the candidates meets the criteria for winning. Under Georgia law, candidates must receive a majority of the vote to win an election. If no candidate breaks 50 per cent, the top two vote-getters then face off again in a run-off election to determine the winner.

Georgia's run-off law was created in the 1960s as a way to preserve white political power in a majority-white state and diminish the influence of black politicians who could more easily win in a multi-candidate race with a plurality of the vote, according to an Interior Department report.

Since the 1990s, Democrats have won only one of seven statewide run-offs in general or special elections, according to Inside Elections, the nonpartisan political newsletter.

Q: Why does Georgia have two run-offs?

A: While Senate elections are staggered so that a state's two seats are not up for re-election at the same time, this was an unusual year for Georgia.

Senator David Perdue, a Republican, was facing a normal re-election race for the seat he won in 2014. In addition, Senator Kelly Loeffler, another Republican appointed last year to succeed Senator Johnny Isakson after he retired because of health issues, was facing a special election to serve out the remainder of his term until 2022.

Both of their races went to run-offs because neither they nor their challengers garnered at least 50 per cent of the vote.

After a prolonged count that ended on Friday night (Nov 6), Mr Perdue fell just short of the majority he would have needed to win re-election against Mr Jon Ossoff, a Democrat, sending both of them to a run-off. In 2017, Mr Ossoff lost in a run-off election for seat in the House.

It has been clear since Tuesday that Mr Loeffler's race would be decided in a run-off after the Reverend Dr Raphael Warnock, a Democrat, and Mr Loeffler emerged as the top two finishers in a crowded field competing to replace Mr Isakson.

Q: When are the run-offs and how do people participate?

A: Georgia's law says the run-offs are to take place on the Tuesday of the ninth week after the election. That puts them on Jan 5. Voters must be registered to participate by Dec 7.

The state will hold three weeks of early voting. Registered voters may vote by mail if they request an absentee ballot.

Q: How are run-offs different than elections on Election Day?

A: It is traditionally more difficult for candidates to convince voters to turn out for elections that do not feature the presidential contest on the ballot, and this special election will come shortly after New Year's Day with the country still in the middle of the coronavirus pandemic.

In the past, Democrats have struggled in such races, with Republicans dominating the format in conservative-learning Georgia.

But both parties are expected to dump ample resources into turning out their voters for the run-offs, and since there are no other races happening around the country, enormous national attention will be focused on Georgia.

The stakes will be high. Republicans hold a 53-47 majority, but after elections this week, they were tied 48-48 with Democrats. While Senate races in Alaska and North Carolina have yet to be called, Republicans are expected to prevail in those states, which would put the party in control of 50 seats.

If Republican leads in those states hold, Democrats would need to capture both of the seats in Georgia to secure a 50-50 tie in the Senate. Then, Vice-President-elect Kamala Harris could cast tie-breaking votes to carry out the Democratic agenda. If they were to lose one, Republicans would maintain their majority, albeit by the slimmest of margins.

With judicial nominees, a stimulus deal, infrastructure and health care measures, and tax and spending policies all on the line, the Senate races in Georgia are likely to take on an intensity that mirrors the presidential race that just ended.

And with President Donald Trump refusing to concede and making baseless accusations that the election was stolen from him, Republicans are likely to try to use their grievances about the presidential race to galvanise their voters to turn out in Georgia and deny Mr Biden the Senate he would need to get things done.

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