By Faith Karimi, CNN

(CNN) -- Georgia's political landscape saw a major shift this election season -- and much of the credit goes to someone who wasn't on the ballot: Stacey Abrams.

In stunning victories, incoming President Joe Biden became the first Democratic presidential candidate to win the state in 28 years and CNN projected Wednesday that Rev. Raphael Warnock will make history as its first Black senator. He will also be the first Black Democrat to represent a southern state in the Senate.

As a nervous nation waited for results of the second of two US Senate races, this one between incumbent Republican David Perdue and Democratic newcomer Jon Ossoff, Abrams remained optimistic.

"With new votes joining the tally, we are on a strong path," she tweeted. "But even while we wait for more, let's celebrate the extraordinary organizers, volunteers, canvassers & tireless groups that haven't stopped going since Nov. Across our state, we roared. A few miles to go...but well done!"

She's key among those organizers. Abrams, the 2018 Democratic gubernatorial candidate, has devoted years to expanding the electorate and boosting turnout in the state, which had been reliably red for decades.

Abrams lost the Georgia governor's race by 55,000 votes in an election marred by allegations of voter suppression. Instead of fading into the background, she climbed into the trenches. She formed an organization to register and empower voters, wrote a book about voter suppression and co-produced an Amazon Prime documentary, "All In: the Fight for Democracy."

Her relentless efforts paid off. No Democratic presidential candidate had won in Georgia since Bill Clinton in 1992, although Barack Obama and Hillary Clinton came fairly close. But Biden got more than 2.4 million votes in Georgia, smashing Hillary Clinton's total by more than half a million.

"Stacey has tirelessly worked to get Joe Biden and the Democratic National Convention to pay attention to Georgia, spending years organizing and strategizing to make sure Georgians have their voices heard at the polls," said Nsé Ufot, CEO of the New Georgia Project, an effort launched by Abrams in 2013 to grow the electorate. "We wouldn't be in the position we are in today without her leadership."

Abrams told CNN that the state has seen dramatic turnout and engagement among communities that are typically not at the top of mind for candidates.

"My heart is full," she tweeted after the November elections. "We are just getting started."

Georgia's demographics are changing

Georgia had voted Republican in eight of the past nine presidential elections. But explosive growth and changing demographics are expanding Democrats' base and turning the state purple. Republicans may no longer be able to count on the Peach State.

Leaders like Abrams, who has pushed Democrats to pay more attention to the state, have helped hasten the shift.

Last year, Abrams and her former campaign manager wrote a 16-page document filled with data and trends on Democratic voters in the state. They described it as a blueprint for victory in 2020.

"With a diverse, growing population and rapidly changing electorate, Georgia is not a future opportunity for Democrats; it is a necessity right now," it said. "Georgia is every bit as competitive as perennial battleground states. With one of the youngest and the most African American electorate of any competitive state, Georgia has demographic advantages that don't exist in other states."

Georgia also has a growing Latino population and booming communities in and around the Democratic stronghold of Atlanta.

The state's shifting demographics have played a key role, but so have investments in recruitment, training and support for candidates from minority communities, Ufot said.

The New Georgia Project said last week it has registered about 500,000 new voters. And it plans to continue knocking on doors.

"We have folks on the ballot who are in our communities, speaking with voters and putting forward policy initiatives that reflect the needs of people within our state," Ufot said. "When people feel heard, they feel encouraged."

Abrams has diversified the state's politics

Abrams, 46, graduated from Spelman College and Yale Law School and served in the Georgia House of Representatives for over a decade.

Seven years ago she founded The New Georgia Project, a voter registration group that has led a grassroots effort to reach and register potential new voters in churches, college campuses and neighborhoods.

After her narrow loss to Brian Kemp in the 2018 race -- which would have made her the first female African American governor -- Abrams launched Fair Fight, which funded and trained voter protection teams in 20 battleground states. It targeted young and minority voters, and educated them on the election and their voting rights.

"We owe Stacey Abrams our greatest gratitude and respect," said Susan Rice, who served as national security adviser during the Obama administration. "Rarely does one person deserve such disproportionate credit for major progress and change."

Abrams' strong 2018 campaign and grassroots efforts have made her a rising star in the Democratic party. In 2019 she became the first Black woman to deliver the official Democratic response to a State of the Union speech.

This year she was among the top candidates considered as potential running mates for Biden. Trump's campaign mocked her, saying she was on a "desperate audition" to become Biden's vice president, but Abrams was not coy about her ambitions.

"As a young black woman, growing up in Mississippi, I learned that if you don't raise your hand, people won't see you, and they won't give you attention," Abrams told CNN's Jake Tapper in April.

"But it's not about attention for being the running mate, it is about making sure that my qualifications aren't in question, because they're not just speaking to me, they're speaking to young black women, young women of color, young people of color, who wonder if they too can be seen."

Abrams campaigned this fall for Biden, and said she gave Democratic leaders a similar pitch.

"I had two messages. One, voter suppression is real and we have to have a plan to fight back. Two, Georgia is real. You've got to have a plan to fight here," she told CNN this week. "We were very privileged to know that by the time Joe Biden won the nomination, he had Georgia on his mind."

Her 2018 loss taught voters key lessons

Many African Americans in Georgia say they were motivated to vote in person by what happened when Republican Brian Kemp ran against Abrams for governor while serving as the state's chief elections officer.

Kemp had enforced some of the nation's most restrictive voting laws as Georgia's secretary of state and was accused during the campaign of seeking to suppress minority votes.

Abrams argued he used his position to sway the election, while Kemp countered that she had "manufactured a 'crisis' to fire up her supporters and raise funds from left wing radicals."

Abrams remained defiant when she ended her bid for governor.

"Let's be clear -- this is not a speech of concession, because concession means to acknowledge an action is right, true or proper," she said. "As a woman of conscience and faith, I cannot concede that. But ... the title of governor isn't nearly as important as our shared title -- voters. And that is why we fight on."

The disputed election outcome also inspired Abrams' organizations to push to register voters in underrepresented communities.

"After 2018, we all continued the fight to make sure that would not happen to the people of Georgia again," Ufot said. "Through grassroots organizing, we have been able to register more voters and get more people to the polls."

Meanwhile, more Democrats across the nation are recognizing Abrams' contributions.

Wisconsin Democratic Party Chair Ben Wikler said this week that her efforts have been felt beyond Georgia.

"There's a lot of totally correct talk about how Stacey Abrams was pivotal to winning Georgia," he tweeted. "Folks: Stacey & her team were pivotal to flipping Wisconsin too. And every other battleground."

Thanks in part to Abrams, Georgia may now be a perennial battleground too.