Donald Trump has lashed out at moves towards his impeachment in a series of angry tweets claiming he has “done more than any president”.
“You don’t impeach presidents for doing a good (great!) job,” he insisted, before accusing his rivals of “treasonous crimes”.
It followed his frequently incoherent speech to Republican members of Congress about the Clean Waters Act, in which he suggested the US was uninhabited until 25 years ago.
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"And so do you. The light is the worst."
Joe Biden is still considered the Democratic front runner but his poll lead has fallen in recent days.
"My AR is ready for you Robert Francis," Briscoe Cain, a Texas politician responded on Twitter.
Mr O’Rourke’s full name is Robert Francis O’Rourke. “Beto” is a childhood nickname which he is known by.
“This is a death threat, representative,” Mr O’Rourke said. “Clearly, you shouldn’t own an AR-15—and neither should anyone else.”
Fellow Democrats, including Alexandria Ocasio Cortez, spoke out in support of Mr O'Rourke following the incident.

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Vice-president becomes 'Mike Pounce' in speech slip-up"Democrats are crying foul after ABC apparently ran an advert showing a picture of representative Alexandria Ocasio-Cortez engulfed in flames, revealing a bunch of skulls behind it, during the third Democratic debates in Houston," reports Clark Mindock.
"The video includes a woman attacking Ms Ocasio-Cortez for her embrace of socialism, and claiming that socialism has led to massacres in the past."
The congresswoman criticised ABC for airing the advert in a series of tweets posted on Friday.
"They profit from burning my likeness on TV," she said.
"But who pays for heightened security? Who answers the phones for the threats resulting from a violent, false ad?"
Read more here: https://www.independent.co.uk/news/world/americas/us-election/aoc-republican-ad-fire-skulls-ocasio-cortez-twitter-tv-advert-a9103456.html
The case alleged violations of the US Constitution’s anti-corruption “emoluments” provisions, which ban the president from accepting gifts or payments from foreign governments without congressional consent.
The negotiations stalled after a failed summit in February between Donald Trump and North Korean leader Kim Jong Un, but the two agreed to revive talks when they met in June at the inter-Korean border.
“By the way today we have the cleanest air, we have the cleanest water that we’ve ever had in the history of our country,” he said.
Mr Trump then appeared to suggest that the history of the US was merely 25 years long.
“Let’s say the history of our country over the last 25 years, I would say that the first few years they probably had cleaner air and cleaner water because there was nobody here.”
The president was speaking in Baltimore, a city which he attacked repeatedly last summer.
He also celebrated a "historic milestone" when the senate approved his 150th federal judge, and sent out some rogue tweets about vaping.
