House Speaker Paul Ryan (R-Wis.) asked Americans to "improve the tone of debate" on social media. (Speaker Paul Ryan)

On Wednesday, House Speaker Paul D. Ryan made an impassioned plea with Americans to “improve the tone of debate.” Critics on the breeding ground of civil discourse known as Twitter used the opportunity to air concerns about Ryan and the GOP.

Lawmakers introduced legislation last month to make July 12 the National Day of Civility — a day to remind people “to be more respectful and polite to others in daily life,” according to the resolution. Although it has yet to clear the House, Ryan (R-Wis.) tweeted a promotional video Wednesday about how we should be more civil.

“I think of our country as this beautiful idea — we call it the American idea,” he said in the video. “Liberty, freedom, free enterprise, self-determination, government by consent of the governed — that's the awesome thing we have here. And we have stressed it, and we have stretched it, and our political dialogue has gotten worse. So what do we do about it? We control our own actions. Let's be more civil. Let's improve our tone. Let’s have a great debate on ideas and principles and solutions instead of ad hominem attacks against one another.”

According to the real-time hashtag tracker Keyhole, the hashtag #NationalDayOfCivility was used by more than 370 Twitter users in the past two days, and more than 50 percent of these tweets had a positive “sentiment.”

Many of the supportive comments came from fellow lawmakers.

However, some commenters on social media, especially in replies to Ryan himself, criticized the speaker, bringing up the Russia investigation, tax cuts and the health-care debate. Others tied Ryan's remarks back to President Trump.

“Big words from someone that refuses to hold a town hall,” one person wrote.

“I wish I'd accept your post without mixed feelings … your party has maligned & belittled people for over a year & NOW you ask for civility?” another person said.

“Maybe you should present the concept to tRump. He's the worst offender. If you think liberals will condone his behavior you are mistaken,” one person wrote.

Another added, “I believe you lost the right to try and unite our country when you let tear through our Stars and Stripes.”

A spokeswoman for Ryan declined to comment.

In an op-ed Wednesday for the Hill, Reps. Charlie Crist (D-Fla.) and Mike Johnson (R-La.) cited a poll showing that about 75 percent of Americans say incivility has reached “crisis levels.”

“These findings, sadly, are not surprising,” the congressmen wrote. “Particularly disappointing was that a majority of Americans believe incivility in our politics encourages general incivility in society, which deters citizens from engaging in public service. Incivility can lead to intimidation, threats, harassment, cyberbullying, discrimination and violence. In the wake of the attack on our fellow members of Congress at a Congressional Baseball Game practice of all places, the need for action could not be more urgent.”

Creating a National Day of Civility, they wrote, is “one small way to give this issue greater attention and spark greater awareness in communities across the country, and in Washington.”

One critic responded in the comment section, “Legislation for bipartisan civility? Don't they have much more pressing issues to address?”

Crist also tweeted about living by the Golden Rule — “always treating colleagues, friends & neighbors w/respect — even if we disagree.”

On Thursday, Crist thanked Ryan “for joining our call for .”

The responses to his tweets were much more muted.

The use of hashtags has often led to unintended consequences, including #myNYPD trending for unintended reasons in 2014 and a pro-Hillary Clinton hashtag that backfired.

After a shooting at a congressional baseball practice in June in which several people were wounded, including House Majority Whip Steve Scalise (R-La.), Republicans and Democrats called for a more civil tone in the political conversation. At the time, Ryan told CNN, “What we're trying to do is tone down the rhetoric, lead by example and show people we can disagree with one another, we can have different ideas without being vitriolic, without going to such extremes.”

In his video Wednesday, Ryan encouraged people to debate, but to do it civilly.

“That is, I think . . . our duty to our country — to help improve the tone of debate, to make it more civil,” the speaker said.

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