For anyone with a computer, tablet or smartphone, social media platforms are an arm's length away. They tempt everyone, minute by minute, hour by hour, to make a wisecrack, a joke or a "profound" comment to show the world how clever they are. Hardly a week goes by when some politician or celebrity is not apologizing for, or explaining away, an errant tweet or post.

This week's case in point — the latest to succumb to the temptation to say something stupid — is Rosanne Barr, with her racist tweet about Valerie Jarrett.

Within a single tweet, "muslim brotherhood & planet of the apes had a baby=vj," Barr managed to offend pretty much everyone. I've seen few shows canceled this quickly that didn't star Tim Conway (a joke that shows my age).

"I apologize to Valerie Jarrett and to all Americans," said Barr in a follow-up tweet. "I am truly sorry for making a bad joke about her politics and her looks. I should have known better. Forgive me — my joke was in bad taste."

But it was too late. Apology not accepted. Show canceled. You're outta here. Next?

To be clear, I found Barr's tweet about Jarrett highly offensive. I don't blame ABC for almost immediately canceling her show, which pre-empted an exodus of advertisers.

Still, the reboot of "Roseanne" had taken the political and entertainment worlds by storm with its astounding ratings and its take on President Donald Trump, which, if not pro-Trump, was notable for not being as hateful toward the president as most shows with a political angle.

Trump supporters celebrated its success, so now its star's demise, taking the show with her, likely will be celebrated by the president's critics. See? We told you so! Just another racist Trump supporter.

That will be unfortunate. I haven't seen every episode of the new "Roseanne," but the first couple were noteworthy for presenting a conversation about Trump that was respectful to both sides. Subsequent episodes I saw barely touched on Trump, but viewership remained strong enough to make the show "the most-watched series of the broadcast season."

Barr has set back the opportunity to have a productive conversation based on the portrayal of a family divided on the question of Trump in a way that reflects reality across so much of the country. Nothing else I'm aware of in entertainment television is addressing that reality in an honest way. The fact that it was drawing millions of viewers each week positioned it to be one of only a few platforms in existence featuring a calm, rational examination of America in the age of Trump, apart from the flamethrowers who dominate so much of what passes for debate on the subject.

Barr no doubt feels sick for herself and everyone associated with her show. She should also hate that what she's done will result in a giant step backward for everyone hoping to get past the knee-jerk accusations that pass for political discourse when discussing the president.

Gary Abernathy is publisher and editor of the (Hillsboro, Ohio) Times-Gazette. He wrote this article for the Washington Post.