Roseanne Barr threw it away.

Plenty of Americans, ourselves included, wanted to believe that Barr’s revived TV show, “Roseanne,” might serve as an emotional bridge in a divided nation, with the Conner family split in their politics but not their affections.

EDITORIAL

Hollywood liberalism is everywhere on TV. We were drawn to the notion of a show from the other side of the tracks, one that punctured lefty self-righteousness while explaining what a lot of us clearly don’t understand — how decent people can be fans of the loathsome Donald Trump.

Looking back, we probably overlooked too much. In our enthusiasm for a show that we hoped — just hoped — might reveal Americans to each other in a more understanding light, we responded only mildly to the many signs that Barr herself was off the decency rails, teetering on the hateful side.

How did we fail to see it back in March when Barr scurrilously accused one of the Parkland High School survivors, in a tweet, of making a “Nazi salute?” What more did we need to know when Barr last year pushed an absurd theory that Hillary Clinton was involved in a worldwide sex trafficking ring?

Now Barr has really gone and done it, out-trolling the creepiest trolls in a racist tweet that forced ABC Entertainment to cancel her show, and that leaves us feeling naive.

We really wanted that bridge.

There is no defending the tweet Barr directed on Monday at one of President Barack Obama’s top advisors, Valerie Jarrett. It read: “muslim brotherhood & planet of the apes had a baby=vj.” For that one tweet alone, ABC Entertainment had no choice but to drop her show.

But, let’s face it, Roseanne has been piling it on for a while now, usually via Twitter. As a people, we’ve just become inured to it all. When your president makes up “facts” every day, mocks people for their disability or their accent, and calls critics “traitors,” your outrage quotient depletes pretty quickly.

Maybe Barr thought it was funny to say that Jarrett, an African-American woman, is the daughter of an ape. Go figure. But she did grow up in a day when a good deal of American comedy, like American politics then and now, was rooted in bigotry and misogyny.

Jackie Gleason, as Ralph Kramden in “The Honeymooners,” liked to slam his fist into his other hand and warn his TV wife, “Some day, Alice, to the moon!” The comedian Bill Dana, playing a slow-witted character named Jose Jimenez, got laughs by doing a fake Mexican accent. Every bad guy in the old “Dick Tracy” comics looked physically deformed.

That was the normal in a by-gone day. Or maybe not so by-gone. Most Americans were blind to the offensiveness then — that’s the excuse we could cop — but we can’t pretend to be blind today.

ABC Entertainment had no choice but to cancel “Roseanne.” The show was named for her. There was no separation between the art and the artist. Every time Roseanne Barr went trolling on Twitter, she made it harder to buy the more civil Roseanne Conner.

Barr let us down. We were looking for that pop culture phenomenon, like the “Roseanne” show, that might help a distrustful nation listen to each other. We’ll have to keep on looking.

But more than that, Barr let down the working class, largely white, Trump-voting Americans for whom she claimed to speak. She said they’re not just a bunch of bigots, whatever the “liberal elites” might say, and of course she’s right. But her own behavior says otherwise.

She betrayed her show’s biggest fans.

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