Looking at the seven regulators arrayed before the Senate Banking Committee, and noting that she had often sat at the same witness table before becoming a senator, she used her new power to question why the federal government has not been more aggressive.

“The question I really want to ask is about how tough you are — about how much leverage you really have,” Warren said. “Tell me a little bit about the last few times you’ve taken the biggest financial institutions on Wall Street all the way to trial.”

A handful of supporters in the packed hearing room applauded. But none of the witnesses — representing the Securities and Exchange Commission, the Commodity Futures Trading Commission and others — offered a response.

“Anybody?” Warren asked, pursing her lips and raising her eyebrows above her glasses.

The hearing was the committee’s semiannual meeting on the Dodd-Frank financial reform act, implemented in 2010 as a response to the financial crisis. The legislation tightened laws regulating big banks and provided safeguards intended to shield consumers from abusive financial practices.

Republicans had been expected to use the hearing to attack the Consumer Financial Protection Bureau, the government agency whose creation that Warren had championed, especially since one of the witnesses was the agency’s director, Richard Cordray.

But the Republicans, without explanation, held back, in effect clearing the path for Warren to take the limelight. The GOP members stuck to broad lines of questioning and did not specifically assail the consumer agency. Ranking Republican Mike Crapo of Idaho instead criticized other Dodd-Frank measures, saying that proposed rules “are far too complex.”

“I’m concerned that the regulators do not understand the cumulative effect of the hundreds of proposed rules, and that there is a lack of coordination among them,” he said.

Warren seized the hearing to chide regulators for not taking legal stands against Wall Street, saying that the threat of trial is an important tool in keeping big banks in line, despite the vast resources required to do so.

“If a party is unwilling to go to trial — either because they’re too timid or they lack resources — the consequence is they have a lot less leverage,” Warren said. “If [banks] can break the law and drag in billions in profits and then turn around and settle paying out of those profits, they don’t have that much incentive to follow the law.”

The regulators often sought to avoid directly answering Warren’s questions regarding their prosecutions.

“The institutions I supervise . . . we’ve actually had a fair number of consent orders,” Comptroller of the Currency Tom Curry said, referring to out-of-court settlements. “We do not have to bring people to trial.”

“I appreciate that you say you do not have to bring people to trial,” Warren countered. “My question is when did you bring them to trial?”

At another point, Elisse Walter, chairwoman of the Securities and Exchange Commission, defended her agency, saying, “We look at the distinction between what we can get if we go to trial and what we can get if we don’t.”

Warren interrupted her: “I appreciate that. That’s what everybody does. The question I’m really asking is, can you identify when you last took the Wall Street banks to trial?”

“I will have to get back to you with the specific information,” replied Walter, her arms crossed.

Warren had pledged to help rein in wrongdoing by big banks when she ran for the Senate last year, and the financial industry poured millions into the campaign coffers of Warren’s Republican opponent — then-Senator Scott Brown — to keep her out of office.

On Thursday, Warren urged regulators to step up the legal actions.

“There are district attorneys and US attorneys who are out there every day squeezing ordinary citizens on very thin grounds and taking them to trial in order to make an example,” she said.

As for taking on banks, she added, “I’m really concerned ‘too big to fail’ has become ‘too big for trial.’ That just seems wrong to me.”

Warren’s performance drew the praise of some fellow Democrats, including Jon Tester of Montana.