McKeon, a longtime aide to Biden, is a senior foreign policy adviser on Biden's campaign. When national news outlets projected the former vice president as the winner of the presidential election, McKeon told The Citizen that he felt a combination of "elation and relief" after four days of vote counting and waiting. 

"We always thought it was inevitable, as reflected in the statements the vice president gave in the last few days," McKeon said. "Looking at the vote count in Pennsylvania and the very consistent data of the mail-in ballots running 2-to-1, 3-to-1 for the vice president, even in the rural counties that went for (President Donald Trump). 

"The mail-in ballots were running 2-to-1 for Biden because the president bad-mouthed mail-in voting and Democrats were urged to get their votes in early as possible. The fact that many of the remaining ballots were coming from southeast Pennsylvania where Biden was doing even better than that — he was doing 3-to-1 or even 4-to-1 in Philadelphia city and Allegheny County and Pittsburgh — it was just a numbers game. It was pretty clear he was going to get far enough ahead that it was going to be decisive." 

The mail-in ballot advantage propelled Biden to victory in Pennsylvania. After he took a 30,000-vote lead, national media outlets projected the former vice president as the winner of the state's 20 electoral votes — enough to put him over the 270 electoral votes needed to win the election. 

Biden's win in Pennsylvania, along with victories in Michigan and Wisconsin, restores the Democratic "blue wall" in presidential elections. Trump won the three states when he defeated Hillary Clinton in the 2016 presidential election. 

Nearly 75 million Americans have voted for Biden, a record for a presidential candidate. He's on track to win 306 electoral votes if he can hold onto leads in Arizona and Georgia, two states Democratic presidential candidates haven't won since the 1990s. 

Biden has described the election as a "battle for the soul of the nation." McKeon believes that message was embraced by voters who view Trump as divisive. 

By contrast, Biden has experience working with members of both parties as a U.S. senator and vice president. In his speeches this week, the president-elect sought to deliver a message of unity to Americans. 

"He's uniquely qualified because he knows the challenges that we have," said McKeon, who noted that Biden is better positioned to address the COVID-19 pandemic and the economic crisis. In 2009 and 2010, the former vice president oversaw the implementation of the Recovery Act amid the Great Recession. 

Biden, McKeon said, will also begin to repair relationships with world leaders, especially some of the United States' longstanding allies. The president-elect has relationships with many leaders, even though there are some new heads of state since he left the vice presidency in early 2017. 

"I think he's going to be able to restore America's credibility," McKeon said. "Trump has done a lot of damage. Don't get me wrong: I don't think that Biden can do everything to restore it on the first day because some countries are wondering whether Trump is an aberration or a symptom of some other issue in our body politic. We'll have to rebuild trust with our allies and partners." 

For McKeon, who graduated from Auburn High School in 1981, he wasn't expecting another campaign or government stint with Biden. He began working in Biden's Senate office in the 1980s. For seven years, from 1988 to 1995, he was Biden's legislative assistant for foreign policy and defense. 

After working outside of Biden's office, including serving on former President Bill Clinton's foreign policy staff during the 1996 campaign, he returned to the Senate in 1997. McKeon was the Democrats' chief counsel on the Senate Foreign Relations Committee, which was chaired by Biden at three different points in the 2000s. 

When Biden was elected vice president, McKeon joined him as his deputy national security adviser. The Auburn native later held other national security posts, including chief of staff of the National Security Council and principal deputy undersecretary for policy at the Department of Defense. 

Before Biden launched his presidential campaign, McKeon was the senior director at the Penn Biden Center for Diplomacy and Global Engagement at the University of Pennsylvania. 

It's too early to say whether McKeon will have a role in the Biden administration. For now, he's enjoying the election win. 

"It's just been a great experience to contribute to the success of this campaign," he said. "It was a big team effort. It was very gratifying because everybody did whatever needed to be done."