Roman Mars couldn't help but laugh this winter when he read a tweet from UC Davis law professor Elizabeth Joh. Then, he retweeted it.

Then, he decided to make (another) podcast.

"She wrote a tweet that said, 'Teaching Con law in 2017 means checking Twitter every five minutes before class,' Mars said. "...I sent her a couple-line email that was, essentially: What would you think about us getting together twice a week to use a Con(stitutional) law lens to react to what Trump had said recently?"

A couple of months and thousands of downloads later, "What Trump Can Teach Us About Con Law" was sitting at number one on the podcast charts earlier this week. Mars, the founder of the hit design podcast "99 Percent Invisible" and the co-creator of Radiotopia, is happy about the podcast's popularity. But he's not exactly surprised.

That's why he decided to launch the podcast unannounced, a la Beyoncé.

"I'm glad it's got an audience, I'm glad it's doing so well, and I felt like it could do it without the kind of support (Radiotopia gives) to other podcasts when they launch. So that's why I dropped it like Beyoncé."

Poynter caught up with Mars to talk about the sudden success of his side-project, the difficulties of balancing two shows at once and what making a more newsy show has taught him about podcasting.

I have tons of questions about your new podcast, if you don't mind me firing them away at you.

I'll do my best.

Did you not have enough on your plate already?

(Cackling) I have plenty on my plate. This podcast came about because I was intrigued by Elizabeth Joh's Twitter and the way that she cast all those Trump things — tweets and various actions — through this Con law lens. I just wrote her. I said, it would be great if we could get together once or twice a week and put this out, and I wouldn't have to cut it into a story. You could just talk and it would be easy.

And the truth is, even someone as experienced as I am can fool themselves into thinking it's going to be no big deal. But I was so excited about the idea of it that I fooled myself all the way to the end. It wasn't until last week that I was like, 'Oh my God, this is really not what I needed right now.'

My other show, 99 Percent Invisible, has grown to such an extent that I have nine people on staff and it takes six weeks to do a story at minimum. And it goes through all these edits. This was a nice thing where I had an interesting conversation and I added a little bit of commentary and could do it in a day or two.

It seemed like fun to me. It reminded me of when I started. And that was the main drive behind doing it.

99 Percent Invisible is this very highly produced podcast. It takes multiple edits, and it's a great product. But I imagine it's very time-consuming. You're also the co-founder of Radiotopia, which has a lot of the same kinds of shows — really highly produced shows. But this is not that. It's more of a conventional interview podcast. Can you talk a little bit about the decision to go that route?

I felt that because we were dealing with stuff that was current events — even though we bring in evergreen explainers about the Constitution — I needed it to not be really hard to produce. I wanted to learn the information and convey it. My favorite part of the show is Elizabeth coming over to my house and teaching me things. I get my own private law professor once a week.

That's the really fun part. And then I have to cut it into something so she'll continue to come over to my house. But I'm fundamentally very interested in design, as evidenced by the shows that I create most of the time. And to me, the key to design is that things should take the form that they're supposed to take.

So with 99 P.I., that means because I'm doing these stories about everyday and often boring things, a lot of the tone of it is trying to seduce people to care about things that are not that interesting on the surface. But then you welcome them in, and through production and the way that voices change and hand off information, it keeps the ear really interested. You create this little gem of a thing to tell a story that you probably wouldn't willingly listen to otherwise, if you were just told the subject material.

But with this one, the immediacy of it and the way that the material can be pretty dry, there's something about the conversational tone, and the exasperated tone on my part — the little gasps and eye rolls I tend to do — fits what it is.

The last two shows that we added to Radiotopia, besides Ear Hustle, which is starting in earnest this week, were The Bugle and West Wing Weekly, which were also considered a little bit of a change of style for us, because they were more conversational and less scripted. With Radiotopia, I think we wanted to establish ourselves as being extremely story-oriented and professional. But it sort of cuts you off from reacting to the world when it takes you eight weeks to do something. So I'm glad we've branched out and the cornerstone of Radiotopia is not necessarily these little gems that take eight weeks. But it's a quality in an overall sense that isn't related to how you talk over music or how many voices you have in a documentary piece.

How did your side project become a Radiotopia show?

Even though I probably could have rammed this show down people's throats, I was very up-front about it. I was like, 'I'm going to do this side project. I'm not sure how much of my time it's going to take. I'm not sure for how long I'm going to do it. And I think it makes sense to be a Radiotopia show. But if you do not want to handle this, I completely understand.'

And luckily, they wanted to add it to the roster.

What does being a Radiotopia show mean? Does it just mean that they're now selling ads against the podcast, as they do for other shows in the network?

That's the bulk of it. They had that for this. But the good part of me doing a new show is that you can pre-sell the ads on shows that I do. I can guarantee that there's an audience for it. But there's a whole lot of technical coordination for launching the thing. There's a whole bunch of tech that (Public Radio Exchange) contributes that makes it viable for us. Dynamic ads and an uploader that makes it all work and registering the iTunes stuff. All of that stuff I didn't have to do. And thank God.

There wasn't a lot of fanfare for this podcast. Why is that?

I really didn't want to put too much of a burden on Radiotopia when it launched. I thought, it probably could find its own audience, it's own legs. And I really wanted to focus on "Ear Hustle," because "Ear Hustle" is a really important project for me and for a lot of people in our shop. And that story needs to be told. Whereas this story is like — I'm glad it's got an audience, I'm glad it's doing so well, but I felt like it could do it without the kind of support to other podcasts when they launch. So that's why I dropped it like Beyoncé.

You mentioned the audience that it's found. What can you tell me about that?

I don't know much about them yet. It's only been since Thursday. I put the intro episode on my feed and the first episode on its own feed. It went to No. 1 on the iTunes chart, which is a kind opaque and almost meaningless, but it feels really good. It has a bunch of downloads — not anything near what 99 P.I. does even on a normal basis. So I don't know yet how well in the long term people are going to take to it. But people seem to be really excited.

No one's been really cranky about it yet, which will happen because a lot of people don't like it if I mention anything political on the other show at all. I understand, but I can't help it. I'm sensitive to the fact that they don't want me talking about Trump on 99 P.I., and I totally respect that, and that's why this is its own thing.

It feels like it's not really a partisan podcast, because almost everyone is in favor of the principles in the Constitution.

That's the idea. I think it would be disingenuous for me to say that I don't have a point of view about it, but there absolutely could be a right-wing podcast that's similar that was like, 'How Obama destroyed the Constitution.' Mainly having to do with executive overreach related to the fact that Congress decided not to legislate for a huge chunk of his eight years.

So in that sense, it could totally work either way. It's definitely not meant to be mean or just griping. It really is, we have this really weird window into this thought processes of Trump through his tweets, and it allows us to have conversations we never could before.

The name of the podcast isn't as sleek as a lot of the other Radiotopia names. Was there a reason why you decided to come out and be a little more straightforward with the name of this podcast?

Yeah. Everything I make has to do with a thing I'm solving in my own psyche from the last thing I created. 99 Percent Invisible was a name I got and then all of a sudden the show made sense to me. It was evocative and it could mean everything and nothing, and I could cover a lot of things a lot of different ways. And then when I started talking about this show with Elizabeth, she said, 'You just want to do a show about what Trump can teach us about Con law.' And it just stuck in my head. And one of the things I loved about it was that it really described exactly what it was. It was not trying to be clever.

As a media reporter, I am contractually obligated to press you for specifics, so I will do that now. You mentioned that it's been downloaded a lot, but not as much as a normal episode of 99 P.I. Can you be any more specific about the number of downloads?

We promised people it would have 100,000 downloads, and we've had at least that. When a new episode of 99 P.I. goes out, we do 400,000 to 600,000 thousand in the first 12 hours. So it's less than that.

You mentioned that you don't really have an arc in mind because President Trump's Twitter is sort of erratic. Is that right?

I'm going to put out one a week because I think people need some regularity. I've recorded a bunch of them. For example, the one I'm putting out on Thursday I had to record four times in different sections because it's about appointment and removal power. He keeps firing people.

There's real danger in working ahead on this show, which is probably good for me. But I think I'm going to put one out a week. And they won't always be completely active to this week or next week.

It seems to me like launching it from the 99 Percent Invisible podcast feed is like launching it from third base. Did you expect it to be this popular?

I thought we would do well, just because we built a good reputation with our audience. I'm not very insular about my recommendations. I have a great love and affinity for my colleagues in Radiotopia. But if there's a good podcast and we can feature them, I do it all the time for different networks. We know that when we feature someone or talk about them, they tend to go to the top of the charts. So my thought was, if I did it, and I was the host of the other thing, it would do well. So it wasn't too surprising.

I tried to let Elizabeth know. She knew my show, and we're fellow parents at the elementary school, so she's familiar with me a little bit. So I was telling her, 'Here's the things that could happen. People could approach you about writing a book. Your profile might be elevated to an extent where people could be meaner to you on Twitter.' She kept saying, 'It's a Constitutional law podcast. There's a bunch of law podcasts. I really don't think it's a big deal.'

It was a delicate thing where I was trying to convince her it could be a big deal but not get her hopes up too much in case it wasn't.

It seems like podcasts are leaning into the news these days. Before, they used to be untethered from the comings and goings of the daily news cycle. And I wanted to ask you whether you'd learned anything about podcasting from something that was much more connected to the news cycle.

I've learned that it's OK to do it. If you'd asked me two years ago — or maybe longer — I would say, 'If you want to make a podcast, make it evergreen, make it non-serialized, make it so you could jump in at any point and have it be fine. All these things that I had learned was necessary to make a podcast with enough audience to gain traction. Then "Serial" changed the landscape.

And then things like "The Daily" and all of the Trump reactions podcasts allow you to follow along and allow you to occasionally be wrong. I think I had this notion that a podcast was this thing preserved in amber as its own document.