The Twitter storm was posted Monday morning just after Blumenthal appeared on CNN and called for continued investigation into alleged meddling by Russia into last year's presidential election.
"Interesting to watch Senator Richard Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist!" Trump said via Twitter @realDonaldTrump.
"Never in U.S.history has anyone lied or defrauded voters like Senator Richard Blumenthal. He told stories about his Vietnam battles and conquests, how brave he was, and it was all a lie. He cried like a baby and begged for forgiveness like a child. Now he judges collusion?"
Blumenthal responded on Twitter via @SenBlumenthal by saying, "Mr. President: Your bullying hasn't worked before and it won't work now. No one is above the law. This issue isn't about me - it's about the Special Counsel's independence and integrity."
At about 4:30 p.m., Trump put out another Tweet on Blumenthal: "I think Senator Blumenthal should take a nice long vacation in Vietnam, where he lied about his service, so he can at least say he was there."
Blumenthal spoke Monday in Hartford about a bill he has introduced that would stop Trump from firing Special Counsel Robert Mueller, who is leading the investigation and recently issued grand jury subpoenas in the Trump-Russia probe.
"The bipartisan measure seeks to forestall the possibility of a constitutional crisis raised by President Trump’s ongoing ominous threats that he will fire special counsel Robert Mueller," Blumenthal said in a statement.
When Blumenthal was first running for the U.S. Senate in 2010 against Republican Linda McMahon, a controversy erupted over a comment he made in 2008 suggesting that he had served in Vietnam. Blumenthal, who was enlisted in the U.S. Marine Corps Reserves in the 1970s, acknowledged that he may have misspoken about his service record but denied lying about it. His service was during the Vietnam era but entirely in the United States.
Trump has blasted Blumenthal on Twitter on the same issue in the past:
In May, after Blumenthal compared the firing of the-FBI Director James Comey to Watergate, Trump fought back on Twitter, calling Blumenthal's statement a "joke" and brought up the Vietnam issue.
Trump did the same thing back In February, when Blumenthal revealed that Neil Gorsuch, then Trump's pick for the Supreme, Court called the president's remarks about judges "disheartening." Gorsuch later acknowledged Blumenthal's statement was true.
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