Stacey Abrams said Tuesday that she won’t run for the U.S. Senate in 2020 but left open the possibility she could launch a presidential campaign.

The decision not to challenge Republican U.S. Sen. David Perdue follows months of speculation about the Democrat’s next political step after her narrow loss in last year’s race for governor.

“I’ve been deeply honored by so many fellow Georgians asking me to serve,” she said in an interview. “But my responsibility is not simply to run because the job is available. I need to run because I want to do the job.”

It leaves Democrats without their top recruit for the Senate race, which has essentially been frozen while Abrams has deliberated. Republicans, gleeful at her decision, rushed to describe the other potential hopefuls as “second-tier” candidates.

And it opens a new round of scrutiny over whether she will join the growing presidential field or emerge as a White House hopeful’s running mate, a possibility that heightened after she delivered her party’s rebuttal to the State of the Union.

If she doesn't make a White House run, Abrams is likely to prepare a 2022 rematch against Gov. Brian Kemp, who bested her by about 55,000 votes in a contest marred by allegations of voter suppression. After 10 days of legal wrangling and vote-counting, Abrams ended her campaign but refused to call it a concession.

Her profile has only grown after that election as she's traveled across the nation on a book tour. She's hit the late-night talk show circuit, attracted sold-out crowds from Nashville, Tenn., to Seattle and drawn huge audiences to podcast tapings.

Closer to home, she's trekked across Georgia on a "thank-you tour" to reconnect with supporters; appeared on local Super Bowl ads to boost her Fair Fight voting rights group, which is challenging state electoral policies in court; and sharply criticized the anti-abortion "heartbeat" measure backed by Kemp.

While her national image has soared, an Atlanta Journal-Constitution poll showed Abrams' favorability ratings in Georgia have dipped. The poll, released in April, showed about 45% of Georgia voters view her favorably, compared with 52% in January. Her unfavorable rating jumped 5 percentage points to 45%.

>> Transcript: In AJC interview, Abrams reveals why she won’t run

Who could challenge Sen. David Perdue in 2020

Stacey Abrams receives a voting sticker with her nephew, Cameron McLean, after casting her ballot during early voting. (ALYSSA POINTER/ALYSSA.POINTER@AJC.COM)

Credit: Alyssa Pointer

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Credit: Alyssa Pointer

‘Friends of Chuck’

Following her defeat, Abrams seemed most likely to make another run for governor, a top objective since age 18, when she made a spreadsheet mapping out her path to the White House. But her rising profile afforded her new options.

In January, U.S. Senate Minority Leader Chuck Schumer offered her the Democratic Party's marquee speaking engagement – its response to President Donald Trump's State of the Union address – while he recruited her to challenge Perdue. He was so relentless that Abrams joked about the frequent calls she got from "friends of Chuck."

He had reason for trying to persuade her to run. Democrats view Georgia as a must-win to recapture control of the U.S. Senate, and Abrams would enter the race with a national profile, proven fundraising ability and a ready-made campaign apparatus.

No Democrat has won a Senate seat in Georgia in nearly two decades, but the party hopes that Perdue’s close ties to Trump and the GOP’s struggles in the densely populated Atlanta suburbs make him vulnerable.

In the interview, Abrams said she was tempted by the possibility of challenging Perdue, who she said has struck “an allegiance with Donald Trump that’s not in the best service of Georgians.”

But she’s long favored seeking an executive role, she said, and stuck with her instincts after much deliberation.

“It’s a job. In the hullabaloo of running for office there’s an amnesia about that. People are interviewing for a job, and the responsibility is to think through that job. And you have to think about what it’s like in the worst day of that job,” she said.

“The Senate is a great institution,” Abrams added. “But, for me, it’s not the role that best suits those needs.”

Even as she closed the door on a Senate run, she pointedly did not rule out a White House bid. She's stoked that possibility in a string of headline-generating appearances, though she's issued no firm timeline on her decision.

“This conversation was about the Senate,” she told the AJC. “I have not decided what I’m going to do about other races, but Georgia will always be at the center of my plans.”

>> Related: Who is Stacey Abrams? 

>> Related: Stacey Abrams' record

Stacey Abrams, left, talks with Sarah Riggs Amico, the former candidate for lieutenant governor, who is considering a run for the U.S. Senate. STEVE SCHAEFER / SPECIAL TO THE AJC

Credit: Steve Schaefer

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Credit: Steve Schaefer

New scrutiny

Even if she stays out of the White House race, Abrams could remain in the national conversation as a possible vice presidential pick.

She’s met with most presidential hopefuls, pressing each on his or her plan to combat voter suppression and compete in Georgia.

The attention has brought new scrutiny. Republicans have mocked her out-of-state travels and cast her as a sore loser for refusing to concede. And she’s facing new questions about the web of organizations she’s started to further her causes.

A Republican-affiliated group filed a complaint with the Internal Revenue Service contending that her voting rights group, Fair Fight Action, is improperly promoting her political ambitions. And the new head of the state ethics commission said he will issue subpoenas for her campaign's bank records.

Abrams' aides call the IRS complaint a "smear job" orchestrated by pro-Trump forces. And her attorney wrote a letter to state ethics officials that said Abrams has "nothing to hide" and will cooperate with the new ethics chief's request.

Republicans were no less scathing in their reaction to Abrams’ decision. The National Republican Senatorial Committee called it Schumer’s “most embarrassing recruiting fail of the cycle” and said it leaves their rivals “stuck with an assortment of second-tier candidates.”

Perdue, meanwhile, sidestepped any mention of Abrams when approached by reporters Tuesday on Capitol Hill.

“Really, nothing's changed,” he said Tuesday afternoon.

“We're going to run against somebody from the Democratic side that's going to be well-funded, and they're going to espouse this radical social agenda that [Democrats are] trying to perpetrate right now, so I'm geared up. We're going to be ready.”

Georgia Democrats, who had grown anxious as Abrams’ self-imposed timetable to decide on a run slipped from March to late April, rushed to praise her.

Former Columbus Mayor Teresa Tomlinson, who said she would run if Abrams did not, now plans to formally launch her campaign Wednesday.

Other potential contenders have waited until Abrams, who said she'll stay neutral in the nominating contest, announced she was out of the race.

They include Sarah Riggs Amico, the runner-up in last year’s race for lieutenant governor; ex-6th Congressional District candidate Jon Ossoff; and Michelle Nunn, who lost to Perdue in 2014.

- Washington correspondent Tamar Hallerman contributed to this article.