“I spent most of my career studying one simple question: Why do American families go broke?” Ms. Warren wrote in a Medium post announcing the policy. “Our research ended up showing that most of these families weren’t reckless or irresponsible — they were just getting squeezed by an economy that forced them to take on more debt and more risk to cling to their place in America’s middle class.”

With less than a month until the Iowa caucuses, Ms. Warren is seeking to recapture the excitement and energy that defined her candidacy early last fall. At the same time, she has generally remained more wary than the rest of the top tier to lob attacks at her opponents.

And despite rolling out her new bankruptcy plan on Tuesday, she made no mention of it in an appearance on ABC’s “The View” or at a large rally in Brooklyn at Kings Theater, where she spoke to an energetic progressive crowd of more than 3,000.

Previously, Ms. Warren had called for the repeal of the 1994 crime bill, another piece of legislation helmed by Mr. Biden that helped reshape the criminal justice system. However, even as Mr. Biden and others have criticized her plans as politically unrealistic and financially infeasible, she has largely avoided returning fire.

Ms. Warren did take one notable swipe at Mr. Biden over the bankruptcy bill: On the day he entered the race, in April, she said the fact that she had sided with consumers and families was a “matter of public record.”