The Associated Press on Wednesday declared Democrat Jon Ossoff the winner of his U.S. Senate runoff election, the second such seat captured by the party in twin contests that were held in Georgia on Tuesday.

Earlier in the day, the AP declared Democrat Raphael Warnock the winner of the other race.

The two victories will give Democrats control of the Senate for the next two years.

Here's a look at the contests:

WHY AP DECLARED OSSOFF THE WINNER

Ossoff held a lead of about 25,000 votes, or about 0.56 percentage points, over Republican David Perdue out of about 4.4 million cast when the AP called the race at 4:20 p.m. Wednesday.

The call was made after an analysis of outstanding ballots showed there was no way for Perdue, who was seeking a second term, to overtake Ossoff's lead.

Tens of thousands of outstanding votes remain to be counted, but the vast majority were in six Democratic-leaning counties that Ossoff was winning.

Many of the ballots left to be counted were mail votes, a form of voting that overwhelmingly favored Ossoff. The remaining votes left to be counted in Republican-leaning areas that favored Perdue were not enough for him to catch up.

Georgia elections officials said there were about 14,000 outstanding overseas and military ballots that had been issued but not returned. Those must be received by Friday in order to be counted. Gabriel Sterling, a top Georgia elections official, said they expected only a fraction of those ballots would be returned in time.

WHAT ABOUT THE OTHER RACE?

Warnock defeated Loeffler after an analysis of outstanding votes showed there was no way for Loeffler to catch up to him with the remaining ballots left to be counted in Republican-leaning areas.

Warnock held a lead over Loeffler of about about 1.2 percentage points, or about 62,000 votes as of 4:15 p.m. ET Wednesday, an edge that is likely to grow as more votes are tabulated.

Almost all the votes left to be counted statewide were mail ballots and early in-person votes. Of those, most are in Democratic-leaning counties.

Warnock was winning mail ballots by 68%, according to an AP analysis conducted early Wednesday morning. And most of the early in-person votes left to be counted were in DeKalb County; that method of voting in the county favored Warnock by about 70 percentage points.

WHAT'S AT STAKE

The outcomes of the two races will help determine the country's political trajectory over the next two years. With Democrats winning both races, they will have a 50-50 seat split with Republicans in the Senate, with Vice President-elect Kamala Harris poised to cast tie-breaking votes.

That would enable President-elect Joe Biden to enact an agenda that includes liberal priorities like raising the minimum wage, approving additional economic stimulus to combat the effects of the pandemic and expanding health care.

But Republicans need to carry only one of the seats to hold a slim 51-49 majority that could serve as a conservative bulwark to limit Biden's ambitions.

The fact that Georgia will determine which of these two dueling visions could become reality speaks to its recent emergence as a swing state. Georgia has been a Republican stronghold for decades, like much of the rest of the South. These two elections are testing just how much the state has changed.

Georgia's government is dominated by the GOP. Until Warnock, a Democrat hadn't won a U.S. Senate contest in the state since former Georgia Gov. Zell Miller in 2000. And until Biden won it by just under 12,000 votes in November, a Democratic presidential contender hadn't carried the state since Bill Clinton in 1992.

But it has slowly morphed into a battleground — a change driven in part by demographic shifts, particularly in the economically vibrant area of metropolitan Atlanta.

As older, white, Republican-leaning voters die, they've been replaced by a younger and more racially diverse cast of people, many of whom moved to the Atlanta area from other states — and carried their politics with them.

Overall, demographic trends show that the state's electorate is becoming younger and more diverse each year. Like other metro areas, Atlanta's suburbs have also moved away from Republicans. In 2016, Hillary Clinton flipped both Cobb and Gwinnett counties. Four years later, electoral maps showed a sea of blue in the more than half-dozen counties surrounding Atlanta.

In 2018, Democrat Stacey Abrams galvanized Black voters in her bid to become the country's first African American woman to lead a state, a campaign she narrowly lost.