U.S. Rep. Ron Barber is clawing his way back in Arizona’s 2nd Congressional District, trailing Republican Martha McSally by just a few hundred votes in his bid for re-election.

Barber was behind by more than 1,200 votes Thursday, but the Tucson Democrat has performed well in Pima County, particularly among on ballots still being counted by Southern Arizona election officials, to tighten the race.

Barber now trails by just 363 votes.

The results pouring in Thursday were a blow to McSally, the retired Air Force colonel who jumped out to a promising lead on Wednesday only to watch it dissipate a day later in a race that’s lived up to its billing as one of the most anticipated congressional elections in the country.

Democrats were confident early Thursday that Barber could recover, based on the way early ballots have swung in favor of the Democrat so far, and based on experiences from 2012 with the early ballots that were counted late.

Barber’s final portion of early Pima ballots in 2012 was 53.6 percent. But D.J. Quinlan, executive director of the Arizona Democratic Party, said he was observing the ballots being counted in 2012 and that more than 55 percent the late-counted early ballots favored Barber then. He expects the same this time.

“Obviously, this is going to be down to the wire, but I’d rather be in Barber’s position than McSally’s,” Quinlan said.

Barber has so far won 54.1 percent of early ballot votes in Pima County, but the late-counted early ballots have favored Barber by a greater percentage. If that trend holds, the race will tighten further still, or could even flip for a Barber win.

Quinlan said the latest counts reflect the calculations he and other Democrats had made, and that he’s hopeful and optimistic that Barber could end up ahead.

For now, the election remains agonizingly similar to the slim margin of victory Barber secured in 2012, when McSally lost after votes were counted for days after election night.

“On Wednesday, Martha McSally was leading by more than 2,000 votes. Today, her lead was cut to a slim margin of 363,” said Barber spokeswoman Ashley Nash-Hahn. “Pima County still has nearly 30,000 votes to count and the trend is mimicking 2012, when Southern Arizona re-elected Ron Barber. We are working to make sure Southern Arizona’s voice is heard and that the integrity of the vote is protected.”

McSally has again outpaced Barber in Cochise County, but far fewer votes are left to count in the Southern Arizona county — officials reported more than 3,000 votes left as of Thursday morning. The Republican challenger has so far increased her margin of victory in Cochise County over her 2012 tally, winning by 59.3 percent there compared to 58.7 percent of the vote two years ago.

McSally urged patience in a statement Wednesday afternoon.

“While the democratic process can be slower than we want at times, it’s critical to making sure all Arizonans have their voices heard,” McSally said. “We worked hard for every vote and we intend to make sure that every vote is counted.”

A Barber comeback would provide a crucial victory for the Democratic Party as it seeks to maintain control of a precious swing district in the House.

For McSally, a highly-touted recruit of the Republican Party, a loss would be a letdown after two years of campaigning following her narrow defeat in 2012, while a win would secure her place as a rising star on the national Republican political scene.

The retired Air Force colonel was a political novice then, but after exceeding expectations two years ago, Republicans expected great things from McSally this year.

McSally has benefited from playing a prominent role in the national Republican spotlight. Roughly $5.5 million was spent on her behalf by outside groups on a mix of ad buys and mailers supporting her campaign and opposing Barber, according to the Center for Responsive Politics, staggering amounts for the inexpensive Tucson media market.

That included $2.6 million spent by the National Republican Congressional Committee, which led all independent expenditure groups in outside spending in the district and routinely touted McSally as a rising star.

McSally also outraised Barber in each quarter this year, and ultimately brought in more than $3.6 million for her campaign.

But Barber was no slouch himself, raising $3.2 million while also benefiting from $5.2 million in outside spending, most of which were expenses for ads attacking McSally.

One of Barber’s most ardent supporters, Giffords and her Super PAC, Americans for Responsible Solutions, mercilessly attacked McSally’s positions on gun control — an issue Giffords has taken up since she was nearly killed in a Tucson shooting in 2011, an attack that also injured Barber.

Giffords’ group spent more than $2 million on Barber’s behalf, and drew national attention with her political ads attacking McSally.

And national Democrats helped redirect spending to help Barber defend his seat in the Southern Arizona district, which is split evenly among Republicans, Democrats and independent voters.