“Why do you keep picking on me?”

It is a question a little brother might ask of a big brother. It would also be a fitting question for Sen. Richard Blumenthal to direct at President Donald Trump. Out of the 100 U.S. senators, Blumenthal stands out as a target of some of Trump’s most mean-spirited tweets.

The latest example came this past week when Connecticut’s senior senator, a Democrat, appeared on CNN. Our president was apparently watching, strange since he contends the news network provides nothing but “fake news.”

Blumenthal expressed his concern that the administration’s crackdown on leakers could go over the line and inhibit the rights of a free press or intimidate whistleblowers. Blumenthal, who has signed onto bipartisan legislation intended to block any attempt by Trump to fire Special Counsel Robert Mueller and halt the continuing investigation into all matters Russian, also referenced the grand juries already underway.

“That investigation must be pursued,” Blumenthal said.

On any given day, you can spin through the channels and find a House or Senate member on a cable news network talking about such things. But in Blumenthal’s case, the result was a Twitter rant from the president.

Bringing up what is old news in Connecticut, Trump again referenced long-past Blumenthal statements in which he suggested serving in Vietnam, when in fact he was a Marine reservist during the war but did not serve overseas. Blumenthal long ago apologized for the statements and has remained a strong advocate for services to veterans.

In Trumpian fashion, the president called the Democratic senator a “phony Vietnam con artist.” He also claimed Blumenthal “told stories about his Vietnam battles.” There is no evidence of that, but why let the facts get in the way of a good insult?

Blumenthal took the high road.

“Mr. President: Your bullying hasn’t worked before and it won’t work now,” he responded on Twitter.

It was the second time Trump went after Blumenthal concerning his Vietnam-era service. Earlier in the year the attack came after Blumenthal claimed Supreme Court Justice Neil Gorsuch, then a nominee, had been critical of Trump’s attacks on the judiciary when he met with senators.

In taking this approach to criticizing Blumenthal, Trump is tossing stones from a glass house. The president received numerous deferments during the Vietnam War, including for alleged “bone spurs” that were discovered by a doctor in the nick of time. Trump didn’t wear the uniform.

Later appearing on the MSNBC political talk show “Morning Joe,” Blumenthal said he was at a loss to explain the president’s personal attacks on him.

“I cannot explain the president’s obsession with me or any of the other targets of his tweets,” he said. “I have no idea what’s in the president’s head.”

ABC News, however, suggests it may be tied to an old Trump grudge. In 1982, Blumenthal married Cynthia Malkin, daughter of real estate tycoon Peter Malkin. The marriage helped make Blumenthal among the richest men in Congress, with a net worth of $67 million, according to Roll Call.

Malkin and Trump have crossed swords in the New York City real estate market, ABC reported. Their most public battle, in the late 1990s, concerned their partial ownership shares in the Empire State Building.

Could that help explain things? Given Trump’s reputation for holding on to grudges, absolutely. But in helping Blumenthal polish his image as the senator who stands up to Trump, the president is likely to improve the standing of the man who is already the most popular politician in the state, polls show.

In trying to demean someone, Trump only demeaned himself. That is also typical of our president.

Paul Choiniere is the editorial page editor.