Democrat Mark Kelly was sworn in to the Senate on Wednesday, marking the first time in more than 67 years that Arizona will have two Democratic senators.

Kelly, 56, a former astronaut and the husband of former congresswoman Gabrielle Giffords (D-Ariz.), defeated Sen. Martha McSally (R) in a special election last month. The seat was once held by longtime Sen. John McCain (R-Ariz.), who died in 2018. McSally was later appointed to the seat but came up short this year in her race against Kelly, who will be up for a full six-year term in 2022.

Vice President Pence administered the oath in the Senate chamber, and Arizona’s senior senator, Kyrsten Sinema (D), accompanied Kelly and held the Bible. All three wore masks. Republicans and Democrats stood and applauded.

Kelly joins Sinema, a former congresswoman who won election to the Senate in 2018, also defeating McSally.

The last time Arizona was represented by two Democrats in the Senate was in January 1953, when Ernest McFarland and Carl Hayden were the state’s senators. McFarland, who was then the Senate majority leader, lost reelection in 1952 to Republican Barry Goldwater.

Kelly was not the only Democrat to claim a statewide victory in Arizona this year: President-elect Joe Biden also won the state, becoming the first Democratic presidential nominee to do so since Bill Clinton in 1996.

The Grand Canyon State’s transformation from a conservative stronghold to a swing state is a result of a decade of work by Mexican American activists, sweeping demographic change and the consolidation of independent voters behind Biden. The dynamics were also influenced by President Trump’s repeated attacks on McCain, whose widow, Cindy McCain, endorsed Biden, and by Kelly’s strong and well-funded campaign.

Giffords watched her husband’s swearing-in from the visitors’ gallery, a rare occurrence as the public galleries in the chamber have been largely closed since mid-March because of the coronavirus.

Giffords retired from Congress after surviving a 2011 assassination attempt by a gunman. She and Kelly have since become well-known advocates of gun control.

“Awesome. A-plus,” Giffords told reporters outside the Senate chamber Wednesday after her husband’s swearing-in.

Kelly simply said, “Great!”

Later, during a ceremonial swearing-in in the Old Senate Chamber, in which Giffords held the Bible, Pence mentioned Kelly’s experience as a former astronaut and said he hoped the new senator would be an advocate for further strengthening NASA.

“You’ll be an invaluable voice building on the progress we’ve made,” Pence said. “We’ve gotten the human space exploration back rolling where it needs to be.”

Tweeting a photo of the ceremonial swearing-in, Kelly wrote, “It’s time to restore science, data, and facts to Congress and be the independent senator Arizona deserves. Thank you for this honor, Arizona.”

In remarks on the Senate floor earlier Wednesday, Senate Minority Leader Charles E. Schumer (D-N.Y.) welcomed Kelly to the chamber and praised him as “a devoted and honorable man.”

“As Mark likes to say, his wife Gabby was already the member of the family in Congress,” Schumer said. “But tragedy upended both of their lives, and changed so many of their plans. Everyone continues to be inspired by Gabby’s recovery, by Mark’s devotion, and the courage it took for their family to re-enter public life and public service.”

On the eve of his swearing-in, Kelly tweeted a photo showing him and his family paying their respects at McCain’s grave Tuesday morning.

“Senator McCain has been a hero of mine since I was a young pilot,” Kelly said in the tweet. “He left a legacy of service to Arizona and country that can’t be matched, but that we should all strive towards.”

Kelly’s replacement of McSally trims the GOP’s Senate majority to 52-to-48 for the last days of the lame-duck session. Two runoff elections in Georgia on Jan. 5 will decide control of the Senate next year at the start of the Biden presidency.

Meanwhile, Trump in recent days has lashed out at Arizona officials — including the Republican governor, Doug Ducey — for certifying the state’s election results and allowing Kelly to be seated.

“Why is he rushing to put a Democrat in office, especially when so many horrible things concerning voter fraud are being revealed at the hearing going on right now … Republicans will long remember!” Trump tweeted Monday.

Despite Trump’s claims, there has been no evidence of widespread voting irregularities in this year’s election, and Attorney General William P. Barr said Tuesday that he has “not seen fraud on a scale that could have effected a different outcome in the election.”

Paul Kane and Jose A. Del Real contributed to this report.