While she claims to be representing “the little guy,” Mr. Brown says, she was actually a “hired gun” for Travelers Insurance against victims of asbestos poisoning and for the LTV Steel Company when it was trying to avoid paying health benefits for its retirees. She earned $350,000 in one year at Harvard, he says, while teaching only one course. …

But she has had a harder time responding to the other claims. On Tuesday, she called a news conference to address the charges that she worked for big corporations, which contrasts with her image as a consumer advocate. …

A lawyer representing the asbestos victims told journalists on Friday that, contrary to Mr. Brown’s assertions, Ms. Warren had stood up for the victims. But Mr. Brown dismissed him as a Democratic donor. And on Saturday he went even further: “Those victims are still waiting for their payments,” he told reporters. “Some of them have died as a result of her efforts.” (Ms. Warren had left the case, and the Brown campaign offered no evidence supporting this assertion.)