John 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 anyone else in Congress is tame. The important thing is that Fetterman intends the description to be an emphatic compliment. “Sometimes I wonder if I’m the embarrassing brother,” Fetterman, the junior senator from Pennsylvania, tells me, referring to the senior senator from Pennsylvania. “He’s an incredibly accomplished senator and just so down-to-earth. He does his job, and that’s refreshing in modern politics. He is not the guy who gets the red counties angry.”

That is indeed a rare quality in this hyperpolarized moment and one key reason Casey, a Democrat, is maintaining a narrow lead in his Senate race against his Republican challenger, David McCormick. The two face off in their first debate on Thursday night in Harrisburg. Casey sounds fired up. Well, calmly fired up. “I think I’ve got a strong record of fighting for workers and for kids, for seniors, for people with disabilities, for our veterans,” Casey tells me. “And while I was doing all that work, [my opponent] was making money by investing in China.”

If this politics business doesn’t work out for Casey, he has the kind of resonant baritone voice that would provide a flourishing career as a late-night FM jazz station DJ. He laughs easily and at length when I relay Fetterman’s “mild thing” assessment. “I haven’t heard that one,” he says. “That’s pretty good. In this turbulent political world, I’ll take that. Most voters don’t want just an argument. They want us to get something done.”

Casey, 64, can point to a record that includes legislation steering money to childcare programs and small businesses. He has also shown an impressive ability to adapt his stances on divisive subjects. Previously 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 overturned Roe v. Wade. “It sounds less offensive when the Republicans say, ‘Oh, the states get to decide,’” Casey says. “Well, the reality is that a ban is not some future thing. There are bans in 14 or 15 states. It’s also the reality of what’s happening because of those bans—a woman in Florida hemorrhaging so badly that she had to be put on a ventilator. I think it’s hard to underestimate the damage that ban after ban can do.”