A simmering feud between conservative lawyer George Conway and Eric Trump spilled into a second day on Tuesday, as the two argued over the issue of wife-respecting.

The spat began Monday when Conway, a frequent Trump critic despite being husband to top Trump adviser Kellyanne Conway, suggested the president had engaged in witness tampering when he tweeted about longtime associate Roger Stone’s vow to stand up to special counsel Robert Mueller.

Conway was referring to the section of the US code that covers witness tampering and obstruction of justice.

George is right. This is genuinely looking like witness tampering. DOJ (at least with a nonfake AG) prosecutes cases like these all the time. The fact it's done out in the open is no defense. Trump is genuinely melting down, and no good lawyer can represent him under these circs https://t.co/zqFUoQvWTf — Neal Katyal (@neal_katyal) December 3, 2018

Perhaps unsurprisingly, Eric Trump sprang to his father’s defense. But in an unexpected move, he assailed Conway’s loyalty to his wife.

“Of all the ugliness in politics,” he tweeted, “the utter disrespect George Conway shows toward his wife, her career, place of work, and everything she has fought SO hard to achieve, might top them all. @KellyannePolls is great person and frankly his actions are horrible.”

Of all the ugliness in politics, the utter disrespect George Conway shows toward his wife, her career, place of work, and everything she has fought SO hard to achieve, might top them all. @KellyannePolls is great person and frankly his actions are horrible. — Eric Trump (@EricTrump) December 4, 2018

Conway has written a number of highly critical op-eds about Trump policies and appointments. Most recently, he suggested in the New York Times that the appointment of Matthew Whitaker as acting attorney general was “unconstitutional” and “illegal”.

In the Washington Post, he argued that Trump’s plan to end birthright citizenship was unconstitutional. He has also publicly referred to the administration as a “shit show dumpster fire” and marshalled a group of conservative lawyers to try to serve as a check on some of the president’s actions.

On Monday night Conway retweeted some of the harsher responses to Eric Trump.

In response to Eric Trump’s ugly tweet, George Conway retweeted three vicious responses from @ianbassin @rezaaslan @renato_mariotti pic.twitter.com/a4dfqCJ7dU — Marcus Baram (@mbaram) December 4, 2018

“Wait. Did I miss something? Did George Conway pay money to have sex with a porn star right after his wife gave birth?” the writer Reza Aslan tweeted in one.

The adult star and director Stormy Daniels claims to have had an affair with Trump shortly after Melania Trump, his third wife, gave birth to their son Barron. Trump denies the claim. Daniels was later paid not to discuss the claim, a move central to former Trump fixer Michael Cohen’s current legal troubles.

This is not the first time the Conway marriage has hit the headlines. In August, after noting that the president finds her husband’s critiques “impolite”, Kellyanne Conway shared her own opinion on the political divide in her marriage.

Her husband’s tweets were “disrespectful, it’s a violation of basic decency, certainly, if not marital vows”, she told the Washington Post, believing she was speaking as “a person familiar with their relationship” and not on the record, before being reminded by the reporter they had made no such arrangement.

For his part, on Tuesday Eric Trump simply retweeted his own tweet. It was a typically Trumpian move. No matter how much blowback you might get for saying something in a tweet, you can always double down.

• This article was amended on 6 December 2018 to correct a misspelling of the name of Trump’s son Barron.