Christine Baranski has played lawyer Diane Lockhart for more than a decade, originating the role in Robert and Michelle King’s “The Good Wife” for CBS in 2009 and starring in their spinoff “The Good Fight” for the Eye’s streaming service, CBS All Access, since 2017. The fourth season of “The Good Fight,” which premieres April 9, starts with a showcase episode for Baranski, in which Diane finds herself in an alternate political world. Soon enough Baranski will further stretch her acting chops in the upcoming HBO series “The Gilded Age” from Julian Fellowes.

In the third season of “The Good Fight,” Diane joined a radical group to try to take down Donald Trump and ended up with SWAT at her door. How is Diane different this season?

The first episode exists almost on its own. It’s like a little prologue, and it doesn’t necessarily launch the whole season or all of the characters, but you could say it launches Diane in another direction. Although I would argue Diane has always been a fighter, it’s the nature of the fight that changes every year with where she puts her energy and how she focuses her intellect and her anger. I really do think there are some marvelous surprises in store for the audience — maybe more than any other season that we’ve had. We’ve never had an episode such as the first episode of the fourth season. When I read it, I said to the Kings, “This is my favorite episode you’ve ever written for me in the 11 years I’ve played the character.” There is something so witty and visionary and nostalgic at the same time. It’s kind of head-spinning that they put Diane in this place — where she wanted to be! Instead of sitting and watching the inauguration of Donald Trump in the pilot to launch the new show, we begin the first episode of the fourth season with her listening to Hillary Clinton be sworn in.

What does Diane learn from living in a world where Hillary Clinton is president?

We live our lives as, “It never would have happened if Hillary had been president. We wouldn’t be in the situation that we’re in now.” You could argue that about this pandemic — because she wouldn’t have fired smart people; she’s not anti-science. Liberal Democrats have this nostalgia for what it might have been and everything we’ve lost because of it. I think the first episode is a brilliant examination of, yes there might have been wonderful things about the Clinton presidency and much would have been avoided, but there was another aspect to the Trump presidency that unleashed an anger that led to a movement that led to powerful men coming down.

What does that mean for Diane for the rest of the season?

In the second episode, Diane begins her new life at this newly-merged, international corporate takeover of our firm. Because we were in such a bad place financially because of the loss of Chumhum and because of the sexual scandal with one of our main partners, we went on board with this STR Laurie, and when Diane enters and sees the newly constructed, refurbished, very cold, very corporate, feng shui environment, it’s amusing to her, but it’s chilly. And she’s called up to meet with the head of the firm, brilliantly played by John Larroquette in utterly perfect casting, and he gives her a whole zen master monologue. She knows she’s in a very strange new world, but he hands her pro bono cases, which, ostensibly, is Diane’s thing. He says, “You’re at your best when you have a cause,” and she’s a fighter for liberal causes and the underdog. So he hands her these cases and says, “Go for it.” Because of that she begins to uncover something going on within the judicial system itself that is deeply disturbing. And I think it’s more disturbing than anything she encountered in fighting Trump. She’s using all of her legal acumen and her passion for the law to figure out why the law is dysfunctional now, and where is it leading?

What does the exploration into that dysfunction look like this season?

There’s something called Memo 618. Why is Memo 618 allowing powerful corporations, powerful men to be exempt from the law — from subpoenas, from judicial rulings? This goes to the heart of the law; this isn’t just one presidency; this isn’t just going after one guy who we think is so wrong for the presidency and what is he doing? She’s taking on something that’s happening in the entire judicial system, and that’s the nuts and bolts of our democracy. So she’s getting into the underbelly of something I think is much more insidious and frightening and potentially very dangerous for my character. If the judicial system isn’t functioning at the very top — I won’t name names, but let’s just say it’s very corrupt: witness the impeachments and the Mueller Report, and why is [William] Barr protecting the president? Is anybody safe? I can’t say, because I haven’t seen the final two episodes, but I did say to Robert King, “You know, where this is going, Diane could find herself behind bars at the end of the season.” He just smiled at me. But for my money, it’s the most compelling plot line I’ve had. But that it begins with, “What if Hillary Clinton was president?” I think is indicative of her wanting to figure out why any of this is happening. It didn’t just begin with Donald Trump, and it’s much deeper than Donald Trump. Guys have been operating in certain ways that has been in place maybe for centuries, maybe for decades, but it has been going on, and there is a system that protects the rich and powerful and certainly men. That is her focus this season, and it just gets very narrow, and it’s chilling, I think.

More than a decade into this character, how do you collaborate with the Kings on Diane’s arc for the season?

I have conversations with them and I say, “Give me a hint where it’s going, let me see a first script as soon as it happens.” But I have absolute faith in them. They’ll run a few things by me for a comfort level, but I’ve always said to them is what makes me happy about being on this show, even more than “The Good Wife,” is it addresses the world and we have to be brave about it. Even last year we did episodes that led to some trouble online and we had some death threats and we faced some very uncomfortable things because we were possibly offending people but it’s very easy to offend people, as we all know, who have a different opinion. So I just let them write the show. I think they’re brilliant writers, and I just want them to write the world that we’re witnessing.

The sense of humor in “The Good Fight” has allowed it to be something of an escape, even when telling these very real, at times scary stories about real-life politics and law. How does that tone feel in the age of coronavirus?

It would be embarrassing for me, with everything going on and all of the harrowing news and the grim reality, to try to promote a show that has nothing to do with where we are as a country and as a world. I’m proud to say that our show, from its inception, has taken on the world and what is going on. If any show has tried to keep up breathlessly with the insanity and the moral laxity and the moral dilemma of our time, it’s our show. We’re dealing with, “If the rule of law doesn’t hold, then where are we?” So I look at our country now and I say, “Why didn’t we have enough masks? What the f—? How did this happen? That was a lapse — a lapse in vision, a lapse in judgement. There was hubris involved there.” Don’t get me started; I’m as angry as Diane!

I think the value of our show is it’s a thinking person’s show, and it pulls you back and makes you say, “Wow, these are characters that are living through what we are living through.” God knows they couldn’t write about this coronavirus because it’s only just surfaced in the last four or five weeks with a vengeance — although we began reading about it in December and January. But it will be very interesting next season, if we have a next season. It’s going to be very hard to ignore this, and it’s going to be really interesting to see how writers and moviemakers and artists address this period of time in the way we address 9/11. It’s going to cut through a hole in our consciousness: Our lives will be before corona and after.

How has the show changed the way you think about or consume politics and news in your daily life?

It’s hard to say, for this character I’ve played for over a decade now, where she begins and I end or I begin and she ends. They’ve tailored this character to my personality, much of it to my rhythms, my humor, my sexuality, my relationship with my husband. They’ve made her a sexual woman at the age of 60, with a wonderful marriage, and I talk to the Kings, and we’re of the same political persuasion, but honestly my family jokes that I’m a bit of a news junky. I don’t have the news on all the time at home now because of my grandsons — because I don’t want to spook. It’s important that children, and I would even say teenagers, don’t watch too much because they have to believe in the world and that the world is a safe place. But every day of working on this show, I have tuned in. It’s morning news, and then I get to my dressing room if I’m working and MSNBC is on, and when I’m not shooting a scene, I go back to my dressing room. I’ve watched it all and stayed really current and it has stoked my fires as Diane, because of course she was, especially the last two years, really in that sense of rage and paralysis over the Trump presidency, being a liberal feminist. You asked if it’s changed me, and everything I read and watch feeds my intelligence and my passion as Diane. The good news is I certainly read the papers, op-ed pieces, foreign affairs; I try and be as informed as I can because I do think we’re living through the most unabashedly crazy period. Hopefully it will be parenthetical to our democracy and there is an end game. Maybe this terrible, terrible virus will shift our consciousness and we will see the inefficiency of this president and this administration.

Things you didn’t know about Christine Baranski:

Age: 67
Hometown: Buffalo, N.Y.
Dream revival: “If I could collaborate one more time with Stephen Sondheim on virtually anything, that would make me happy.”
Favorite part about shooting in New York: “I just get to be home. I get to go home at night and I get to be near my family and my friends.”
Currently reading: “Material on the Gilded Age because I have been in preparation for that but I’m also going to start reading ‘These Truths: A History of the United States’ by Jill Lepore.”