As a student at Pennsbury High, Yardley native Robert Costa wrote about music for the Bucks County Courier Times. (One claim to fame: persuading Maroon 5 and John Mayer to play at the school.) These days, he's juggling a full-time job at the Washington Post, where he covers Congress and the White House, with political analysis at NBC and MSNBC.

On April 21, Costa, who has degrees from Notre Dame and the University of Cambridge, added a new role, succeeding the late Gwen Ifill as permanent moderator of PBS's Peabody-winning roundtable show, Washington Week (8 p.m. Fridays, WHYY TV12).

He spoke with Ellen Gray about keeping his opinions to himself, getting to know Bernie Sanders and Donald Trump, and that time the president of the United States called him on his cellphone.

Gwen Ifill once said her job "as a reporter is not to know what I think." You've worked for the National Review, and now you report for the Washington Post, which are perceived to be different places, politically. Does that make you a good choice to moderate a show that's meant to be nonpartisan?

It's always been my goal to be simply a reporter. Not right, not left, just the facts, and, if I can, to provide some insight. I've never been comfortable expressing my opinion. When I was at National Review, I was a reporter, covering the American right, and populism, and the tea party movement. Even though I was at a conservative publication, it was important to me to cover conservatism objectively and to have at times a skeptical eye. At the Washington Post, I have a note on my desk, and it says, "Assume nothing."

When I saw Sen. Bernie Sanders start to rise on the left, a lot of people in the media shrugged, and said, "He'll go nowhere." But he and I spoke regularly, we developed a rapport, reporter to source. Same with President Trump. People assumed he'd go nowhere, that he was this strange figure in American politics.

You've been a frequent guest as well as a guest moderator. Is it more fun to be the moderator?

It's been real fun to be a guest. I'm going to try to thread my reporting from the week into some of my questions, but I really want to bring out the best in the guests, and to showcase the reporters who are generous enough to come on on a Friday night.

President Trump recently called your cellphone to tell you he was pulling the health-care bill -- what was that like?

It's wild. I've known President Trump for quite some time as a reporter, going back to an interview I did with him in the summer of 2013, the first interview where he ever spoke about his interest in running in 2016.  And he was talking about the same things then -- trade, immigration, America's not winning enough, that he talked about during the campaign. What was intriguing to me, early on, in 2013, 2014, 2015, as a reporter, was how accessible Trump was. A lot of people in national political journalism weren't interested in actually talking to him.

Your beat's a busy one -- does being on TV bring something to your reporting that makes the extra time worthwhile?

I think sources, lawmakers, people at the White House definitely pay attention to television. And they pay attention to who's a straight shooter. I think politicians in both parties are often just looking for people who are trying to understand them. Not people who like them, or people who hate them, but people who are just trying to understand.

Personal question you don't have to answer: Do you have a personal life?

I'd like to think I have some balance. I go to church on Sundays at St. Matthew's [Cathedral] in D.C. I'm single. I'm 31. But, you know, I go on dates. I go to movies. I love rock concerts, which I used to cover all the time in Philly.

What, besides cellphone calls from the president, has been different about covering this administration, compared to the last one?

Oh, my gosh. Everything is different. This White House moves at such a frenetic pace. You have to be constantly checking in with sources about who's up, who's down, and what's the actual policy now. There are factions within this White House that are ever-changing. And so I almost keep these diagrams in my notebook about who's aligned with who now. But as wild as it is, it's also fun. People have different views about President Trump, understandably, but as a reporter, it's this train that never stops.