A bipartisan group of senators led by Massachusetts freshman Democrat Elizabeth Warren introduced a bill Thursday to reinstate the Great Depression-era Glass-Steagall law that would separate commercial from investment banks.

Speaking at a Senate Banking Committee hearing on the implementation of the Dodd-Frank financial reform law, Warren said that the point of her bill was “keeping the gamblers out of our banks.” Sens. John McCain, R-Ariz., Maria Cantwell, D-Wash., and Angus King, I-Maine, are co-sponsoring the measure.

The new Glass-Steagall provision, intended to counter the threat of too-big-to-fail banks, would separate banks that offer savings and checking accounts to consumers from firms that engage in other, riskier financial services, such as investment banking and hedge fund management. The non-commercial banks would not be insured by the Federal Deposit Insurance Corporation.

The Dodd-Frank Act includes a measure intended to prevent banks from speculating with consumers’ accounts known as the Volcker Rule. The new bipartisan proposal would be a far more stringent preventative measure than the Volcker rule. Many critics of current Wall Street regard the Volcker Rule, which hasn’t been finalized, as too weak or containing too many loopholes to be effective.

Anti-bank populism was a key feature of Warren’s 2012 campaign and the reason for her popularity among liberal grassroots groups. Before running for office, she was the chairman of the Congressional Oversight Panel, a group formed in 2008 to oversee the Troubled Asset Relief Program (TARP) and other bailout programs. In that role, Warren became known for combative questioning of Treasury Secretary Timothy Geithner and other administration officials about the Treasury’s treatment of big banks and mismanagement of the housing relief program.

Warren and King, both in their first year as senators, join McCain and Cantwell, who have previously pushed for a reinstatement of Glass-Steagall. McCain had supported the repeal of the original Glass-Steagall in 1999 with the Gramm-Leach-Bliley Act, but favored the measure following the financial crisis.

The bill marks bipartisan unease with the size of the biggest banks and their importance in the larger economy. “The four biggest banks are now 30 percent larger than they were just five years ago, and they have continued to engage in dangerous, high-risk practices that could once again put our economy at risk,” Warren said.

Nevertheless, the bill has almost no chance of becoming law. Recent attempts to crack down on big banks have failed to garner wide support, including a recent bill from Senators David Vitter, R-La., and Sherrod Brown, D-Ohio, that would have raised capital requirements for the biggest banks. Similar efforts failed to gain traction during the drafting of Dodd-Frank.

Warren announced the bill to top financial regulators at a hearing on systemic risks to the economy posed by big banks. Officials from the FDIC, Federal Reserve, the Treasury Department, and the Office of the Comptroller of the Currency were testifying on the implementation of Dodd-Frank and the adoption of the international Basel III capital regulations intended to prevent future bailouts and banking crises.

Brown noted at the hearing that the banks regarded as systemically important, or too big to fail, would be relatively unaffected by the regulators’ proposed new capital rules. Brown cited a Financial Times report that the implementation of the Basel III regulations in the U.S. wouldn’t force the big banks to raise additional capital to protect against unforeseen shocks.