Weld, a former Massachusetts governor and U.S. attorney in the Bay State, should be lambasted by all Americans for those comments, Levin said Monday on "The Mark Levin Show on Westwood One."
"This should be an absolute controversy that William Weld just accused the president of treason – pure and simple – and then said the only penalty is 'death'," he said.
"I worked with Bill Weld. Bill Weld is a conniving, unethical [person]," Levin added, recalling the two men's time working in the Reagan Justice Department. Levin was chief of staff to then-Attorney General Edwin Meese and Weld was the head of the Criminal Division.
Levin told his audience how Weld, then-Deputy Attorney General Arnold Burns, and other top aides resigned, amid what he characterized as an attempt to urge Reagan to fire Meese.
"And they failed... And he did all this to position himself to run for governor of Massachusetts. He's doing a similar thing against President Trump. The man is utterly unprincipled. And I'll prove it to you," he said playing a clip from Weld's appearance on MSNBC.
On the network's "Morning Joe" program, Weld claimed Trump has "now acknowledged that, in a single phone call right after he suspended $250 million of military aid to Ukraine, he called up the president of Ukraine and pressed him eight times to investigate Joe Biden."
"Talk about pressuring a foreign country to interfere with and control a U.S. election. It couldn’t be clearer, and that’s not just undermining democratic institutions. That is treason. It’s treason, pure and simple, and the penalty for treason under the U.S. code is death. That’s the only penalty."
Weld continued, remarking it could be a "pretty good alternative" for Trump to offer a "plea" for the Constitutional remedy instead: removal from office.
Reacting to the clip, Levin further criticized Weld's character.
"Listen to this," he said. "This is how sick this man is: 'The penalty of treason under the U.S. code is death'?"
"He doesn't have a chance in Hell of getting one percent of the vote... This man wants to be president of the United States. He doesn't even qualify to be a host on MSNBC or CNN."
In 2016, Weld ran for vice president on the Libertarian Party ticket with former Gov. Gary Johnson of New Mexico.