WASHINGTON – A Senate measure advertised as protecting taxpayers from another Wall Street bailout would still leave them fronting the money if the government moves to liquidate a big failing company like insurance giant AIG.

Taxpayers could end up putting up billions of dollars to cover the costs of dealing with such a firm and be able to recoup that money only over a period of five years, under the Senate’s sweeping overhaul of financial regulations.

An amendment the Senate is expected to pass today states that “taxpayers shall bear no losses from the exercise of any authority under this title.” Sen. Richard Durbin, D-Ill., said Monday the legislation means: “We’re never going to let the taxpayers and Treasury face this kind of obligation.”

But the measure doesn’t prevent that kind of obligation, though it does require that taxpayers would be paid back.

“The bill ensures taxpayers don’t get stuck paying for Wall Street’s mistakes,” said Kirstin Brost, a Democratic spokeswoman for the Senate Banking Committee.

The government would have top priority getting repaid, with proceeds of the sale of a liquidated firms’ assets going to the government first.

Financial experts argue it would be irresponsible to preclude the use of taxpayer money in the middle of a financial crisis.

“You can put your head under the cover and pull the blanket up, but you can’t make systemic risk cost-free,” said Karen Shaw Petrou, an analyst with the consulting firm Federal Financial Analytics.

Other steps the Senate intends to take could mean taxpayers could end up fronting even more money.

The legislation aims to avoid the billions of dollars in taxpayer-backed infusions that prevented AIG, the insurance conglomerate, from becoming a disastrous financial drag in late 2008.

It would set up a mechanism to dismantle or liquidate giant, interconnected failing firms by requiring that the costs of bringing them down be borne first by shareholders and creditors and, if need be, by some of its largest peers in the industry.

But most agree that such a massive undertaking would carry additional costs.

The Congressional Budget Office estimates that the government’s 10-year cost of liquidating large firms, after the sale of assets, would be $26.3 billion. That would be the amount the government would have to put up before collecting from the financial industry.

Democrats and Republicans have agreed to scuttle a provision in the bill for a $50 billion fund financed by large financial institutions to cover initial liquidation costs.

Republican senators argued that the mere existence of that fund could encourage large firms to make risky investments.

Instead, the bill will provide that the Federal Deposit Insurance Corp. borrow the money from Treasury and then try to recoup it later from shareholders, creditors and the sale of the liquidated company’s assets. The bill requires that any additional costs be recouped from the financial industry.

“If you try to get the money after the fact, it may be much harder politically to do,” said Douglas Elliott, a former investment banker and now a fellow at the Brookings Institution.

“Then the taxpayers really might bear some of the costs.”

Any possibility that the public will perceive the legislation as a bailout of the industry has spooked lawmakers.

The $700 billion Troubled Asset Relief Program, which the Bush and Obama administrations used to infuse money into banks reeling from the recession, has been a political albatross.