WASHINGTON _ President Donald Trump likes to taunt his enemies, but he seems to have a special place in his Twitter thumb for Connecticut Sen. Richard Blumenthal, the Democrat who was talking about the Russia investigation on CNN Monday morning.
Trump has mentioned Blumenthal in six tweets, on three separate dates since February, according to the Trump Twitter Archive.
Each time, Trump has maligned Blumenthal for misrepresenting his military service during the Vietnam War, an ironic line of attack from a president who received five deferments from the draft and never served in the military.
Trump's lack of military service is not unusual for a president.
Presidents Bill Clinton and Barack Obama both lacked military service, and President George W. Bush sparked some controversy with his service in the Texas National Guard during the Vietnam era. He was not deployed abroad.
President Ronald Reagan was never sent overseas during World War II, spending some of that time producing training films for the Army Air Forces. President Jimmy Carter and President Gerald Ford both served in the Navy, and President George H.W. Bush was a Navy pilot in World War II.
None of those presidents was as aggressive in calling out others on the issue, though.
Trump called Blumenthal a "phony Vietnam con artist" in one tweet on Monday and said he "defrauded voters" in another. Back in February, he accused him of a "major lie" on the subject. In May, he alleged Blumenthal committed "one of the greatest military frauds in U.S. history."
"Interesting to watch Senator Richard Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist!" Trump tweeted Monday.
Indeed, Blumenthal was forced to apologize in 2010 for saying he had served in Vietnam, when in fact he served in the Marine Corps Reserves during the period.
Trump's military history has come up several times, including during his public feud with the Muslim family of a fallen soldier during the presidential campaign.
Trump graduated in 1968, with four draft deferments for being a student that allowed him to avoid compulsory service.
After that, he received a fifth for bones spurs in his heels. He called the condition "temporary" and "minor" in an interview last year with The New York Times.
"I had a doctor that gave me a letter _ a very strong letter on the heels," he told the paper.
In a 2015 news conference, Trump forgot which heel had been diagnosed, before his campaign clarified that it was both of them.
Blumenthal, for his part, claimed the "bullying" was not getting to him.
"This issue isn't about me," he tweeted. "It's about the Special Counsel's independence and integrity."