The plan, which she described as “economic patriotism,” is part of Ms. Warren’s effort not only to replace Senator Bernie Sanders of Vermont as the standard-bearer for liberal Democrats, but also to appeal to the working-class voters in the Midwest who voted for President Trump in 2016.

[Ms. Warren and Mr. Sanders of Vermont are jockeying to represent the party’s left wing.]

After the first commercial break, Ms. Warren was joined by two of those voters, as well as one who voted for Hillary Clinton and one who wrote in Mr. Sanders. The Trump voters, Renee Elliott and Susan Cropper, said they had been sold on Mr. Trump’s promises to save manufacturing and other jobs in states like Indiana, but now felt betrayed.

“I feel duped,” Ms. Elliott said. “I don’t have a lot of faith in political candidates much anymore. They make promises, and they make them and break them.”

“The thing is, you can’t just wave your arms,” Ms. Warren said in response. “You’ve really got to have a plan, and” — her frequent refrain — “I do have a plan.”

She went on to outline this week’s economic proposal, as well as her universal child care plan and her proposed wealth tax: 2 cents on every dollar of wealth above $50 million, with an additional 1 percent tax on assets over $1 billion.

“I get why people feel discouraged,” she said. “But the bottom line is, this is a democracy. And in a democracy, we need our budget and our numbers to align with our values, and our values are not that the top one-tenth of 1 percent keeps their two cents and nobody else gets it.”

Mr. Hayes broke in, questioning Ms. Warren sharply on the feasibility of her plans. “They’re Mitch McConnell’s values,” he said, referring to the Senate majority leader.