Donald Trump said in a tweet that if he is removed from office, a "civil war" might erupt in the United States. The president was quoting Pastor Robert Jeffress, a Fox News contributor and host, who suggested that impeaching the president would lead to "civil war."

"If the Democrats are successful in removing the President from office (which they will never be), it will cause a Civil War like fracture in this Nation from which our Country will never heal," Mr. Trump tweeted, attributing the quote to Jeffress.

Jeffress did more or less say that on "Fox & Friends" — with Mr. Trump adding his thoughts in the parenthesis of the tweet, saying he will never be removed from office. The president's repetition of the quote received widespread backlash — including from his own party.

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"I have visited nations ravaged by civil war," Republican Rep. Adam Kinzinger tweeted. "@realDonaldTrump I have never imagined such a quote to be repeated by a President. This is beyond repugnant." Kinzinger is a veteran and serves on the House Foreign Affairs Committee. He often criticizes the president on Twitter, although he is one of the only Republicans to publicly criticize the Mr. Trump's call with the Ukraine leader.

I have visited nations ravaged by civil war. @realDonaldTrump I have never imagined such a quote to be repeated by a President. This is beyond repugnant. https://t.co/a5Bae7bP7g — Adam Kinzinger (@RepKinzinger) September 30, 2019

Democratic Representative Ted Leiu supported his colleague across the aisle, tweeting: "I agree with Republican Representative Adam Kinzinger that @realDonaldTrump's tweet about a civil war over impeachment is beyond repugnant."

Mr. Trump's civil war tweet went viral, and by Monday #CivilWar2 was trending on Twitter, as was #CivilWarSignup.

While some made fun of the potential of another civil war, many Twitter users pointed out that inciting civil war could encourage violence.

Oath Keepers Militia, which is identified by the Southern Poverty Law Center as "one of the largest radical antigovernment groups in the U.S. today," embraced Mr. Trump's civil war suggestion. "This is the truth. This is where we are. We ARE on the verge of a HOT civil war," the group wrote.

"Like in 1859. That's where we are. And the Right has ZERO trust or respect for anything the left is doing. We see THEM as illegitimate too," continued the tweet, which appeared to be signed by Oath Keepers leader Stewart Rhodes.

Here’s the money quote from that thread. This is the truth. This is where we are. We ARE on the verge of a HOT civil war. Like in 1859. That’s where we are. And the Right has ZERO trust or respect for anything the left is doing. We see THEM as illegitimate too.@StewartRhodesOK https://t.co/DjB8TY0vCo — Oath Keepers (@Oathkeepers) September 30, 2019

Other Twitter users also suggested that inciting a civil war should be an impeachable offense.

As of Monday, over 90% of the 235 Democrats in the House of Representatives either support impeachment proceedings against President Trump or have signaled they are open to supporting them.

The formal impeachment inquiry was announced by House Speaker Nancy Pelosi soon after the president admitted he had asked the Ukrainian president to investigate former Vice President Joe Biden and his son. Pelosi said Mr. Trump's actions represent a betrayal of his oath of office, of national security and of the integrity of U.S. elections.