Johannes Fetterman has a nickname for Bob Casey: “I call him ‘Mild Thing.'”

Of course, compared to the tattooed, cargo-short-wearing, profanity-spewing wild thing Fetterman, pretty much everyone in Congress is tame. Most importantly, Fetterman intended the description as an emphatic compliment. “Sometimes I wonder if I’m the embarrassing brother,” said Fetterman, the junior senator from Pennsylvania, referring to the senior senator from Pennsylvania. “He is an incredibly talented senator and just so down to earth. He does his job, and that is refreshing in modern politics. He is not the man to anger the red provinces.”

That’s a rare quality indeed in this hyper-polarized moment and a key reason why Casey, a Democrat, maintains a slim lead in his Senate race against his Republican challenger: David McCormick. The two will face off in their first debate in Harrisburg on Thursday night. Casey sounds excited. Well, nice progress. “I think I have a strong record of fighting for workers and for children, for seniors, for people with disabilities, for our veterans,” Casey says. “And while I was doing all that work, (my opponent) was making money investing in China.”

If this political stuff doesn’t work out for Casey, he has the kind of resonant baritone voice that would land him a flourishing career as a DJ on the late-night FM jazz station. He laughs easily and for a long time when I relay Fetterman’s “mild” assessment. “I haven’t heard that one yet,” he says. “That’s pretty good. In this turbulent political world I accept that. Most voters don’t just want a fight. They want us to get something done.”

Casey, 64, can point to a file that includes legislation that sends money to child care programs and small businesses. He has also shown an impressive ability to adjust his positions on divisive topics. Formerly, but not monolithically pro-gun and pro-life, Casey embraced gun control after the Sandy Hook massacre and the codification of national abortion rights after the Supreme Court struck down the law. Roe v. Wade. “It sounds less offensive when Republicans say, ‘Oh, the states get to decide,’” Casey says. “Well, the reality is that a ban is not a thing of the future. There are bans in 14 or 15 states. It’s also the reality of what happens as a result of those bans: a woman in Florida bleeding so badly she had to be put on a ventilator. I think it is difficult to underestimate the damage that ban after ban can do.”

That Casey has managed to deal with such incendiary issues and remain a healthy moderate, both in style and substance, has been crucial to his political longevity. Probably even more important is his unwavering attention to local issues in Pennsylvania. In his current campaign, that has meant returning again and again to the pocketbook arguments, emphasizing that he and the Democrats are on the side of the middle class, while McCormick — a multimillionaire — and the Republicans are rooting for the rich. “Senator Casey has done a great job of inoculating himself, even before election season, of talking about ‘greed,’ of talking about going after those who are gouging consumers,” says Mike Mikus, a Democratic strategist based in southwestern Pennsylvania.

In the presidential election, Pennsylvania is a must-win state Kamala Harris, and she’s clearly paying attention to what works for Casey. Some of his personal strengths — such as a familiarity with Pennsylvania voters dating back to his father, who was governor for two terms — cannot be transferred. But the winning formula, statewide, also for Democrats in Pennsylvania Joe Biden in 2020, it was keeping the losing margins in check in rural areas while the score went up in Philadelphia and Pittsburgh — and, crucially, capturing enough voters in the suburbs and exurbs outside the two big cities. This is where Casey’s strategy becomes applicable to Harris’ campaign. “One of Casey’s central arguments is that companies are getting a good deal right now and they’re screwing over workers,” says a national Democratic Party strategist. “That resonates and it has allowed Casey to attract a very broad coalition of voters, which includes many Republicans.”