WASHINGTON — As the fallout from the Iowa caucuses continues, Rep. Andy Kim, a swing district Democrat from South Jersey, has endorsed Pete Buttigieg for president.

Kim became the most prominent elected official in the Philadelphia region to endorse Buttigieg, who is riding high after finishing in a virtual tie for first place in Iowa, the first state to hold a 2020 nominating contest.

Most elected Democrats in the region who have announced endorsements have sided with Joe Biden. But the former vice president is facing sharp questions about his viability after a distant fourth-place Iowa finish. Buttigieg, the former mayor of South Bend, Ind., is now arguing that he, not Biden, should be the standard-bearer for more moderate Democrats concerned about appealing to swing voters.

In Iowa, Buttigieg won 21 of the 31 counties that voted twice for Barack Obama and then flipped to Donald Trump.

Kim, 37, and Buttigieg, 38, are friends who have known each other for years. They were part of the same Rhodes Scholar class at Oxford University in the mid-2000s, and both have national security backgrounds. Kim was a national security adviser in the Obama administration, while Buttigieg served as a Navy intelligence officer in Afghanistan.

“I know Pete, I trust Pete, and I believe he’s ready to move our country forward,” Kim said in a statement. “I’ve known him nearly half my life, we shared the joys of each other’s weddings, and we had hard conversations about deployments to Afghanistan and what it means to serve our nation.”

He added: “There were three traits that I look for in a president: Have they been tested, do they know how to make a decision, and do they have a strong moral compass and a capacity for empathy where they can put themselves in other peoples’ shoes. Over the years I’ve seen Pete not only step up to face some of our nation’s toughest challenges with calm and precision, but he also truly cares about helping people live their best lives."

On Friday, former congressman and past 2020 presidential candidate Joe Sestak of Delaware County endorsed another moderate in the race, Sen. Amy Klobuchar of Minnesota, also citing her ability to perform well in swing districts.

“We need a nominee with a depth and breadth of experience to govern effectively, a proven track record of winning in red and blue districts and states so we can unite this country again," Sestak said in a statement. He plans to campaign for Klobuchar in New Hampshire this weekend ahead of Tuesday’s primary vote.

In 2018, Kim flipped a Republican-held House district in Burlington and Ocean Counties that Trump had won in 2016. Other Philadelphia-area Democrats in similar battlegrounds have endorsed Biden, including Reps. Chrissy Houlahan of Chester County and Susan Wild of Lehigh County. So has Rep. Conor Lamb, from outside Pittsburgh. Reps. Brendan Boyle and Dwight Evans, both of Philadelphia, as well as Pennsylvania Sen. Bob Casey also support Biden.

Another similarly situated Democrat from North Jersey, Rep. Mikie Sherrill, who also won a previously Republican-held district, endorsed billionaire Mike Bloomberg Thursday. Kim and Sherrill had previously endorsed their home-state senator, Cory Booker, before he dropped out of the race.