"I think an assault weapon ban can be revived at the federal level. I think that is practical and feasible, especially with the kind of change in debate that I would anticipate," Blumenthal said on MSNBC's "Morning Joe."
Sen. Dianne Feinstein (D-Calif.) on Sunday vowed to introduce legislation to reinstate a federal ban on assault weapons on the first day of the new Congress in January.
President Obama “is going to have a bill to lead on,” Feinstein said on NBC’s “Meet the Press.” The measure, she said, would aim to take “weapons of war off the streets of our cities.”
She said the bill would also "prospectively" ban the sale, transfer, importation and possession big clips, and drums or strips of more than 10 bullets.
Blumenthal predicted that the death toll in Connecticut — which included 20 children — would "spur and change" the debate over gun violence.
"I think it is transformative. I think it will spur and change the debate and national discussion, beginning with the president's statement last night ... what my colleague Joe Manchin said earlier on this show, I think are really very, very powerful signs that we've entered a different era in this discussion," he said.
Earlier on MSNBC, Sen. Joe Manchin (D-W.Va.), who has an "A" rating from the National Rifle Association, said he was open to discussing the assault weapons ban being introduced by Feinstein and said "everything should be on the table."
Blumenthal, who served as Connecticut's Attorney General, said he is hearing from former colleagues in law enforcement that "we need to do something."
The Connecticut lawmaker praised the residents of Newtown as "resilient and resolute."
"I think Newtown will heal. It is a strong and vibrant town, bound together by countless relationships that are deeply rooted, and I've been at the vigils and the church services, the firehouses and people there are resilient and resolute. It is the quintessential small New England town and exquisitely beautiful," he said.
Blumenthal told MSNBC that residents of Newtown are calling for action to be taken to help prevent another similar incident in the future.
"The assault weapons ban, the ban on high capacity magazines, mental health efforts. We need to do something. That is what I hear from so many people in Newtown, as well as elsewhere across the country," he said.
— Daniel Strauss contributed to this report.