The banks want California, and the Obama administration hopes they can get it.

In September, the attorney general of California, Kamala Harris, withdrew from settlement talks between the banks and federal and state officials over mortgage abuses. Ms. Harris said California was being asked to excuse bank conduct that has not been adequately investigated and to grant the banks an unacceptably broad release from legal liability for the mortgage mess.

Those grave reservations have also been raised by other state attorneys general — including Eric Schneiderman of New York and Joseph Beau Biden III of Delaware. The administration, however, wants a deal. As pressure builds to get on board, Ms. Harris and her like-minded peers should stand their ground and avoid letting the banks off easy.

The administration says a settlement today would quickly deliver relief to needy borrowers. That’s true as far as it goes, but it doesn’t go far enough. Early word of the proposed settlement indicates that banks would reduce the balances on a million or so underwater loans by $17 billion to $20 billion. They would put up $5 billion to $8 billion to help pay for refinancings, counseling, legal services and other aid to homeowners. And they would have to adhere to tougher standards for loan servicing and foreclosures. That would be better than now but paltry compared with the potential extent of bank misconduct and with the scale of the mortgage debacle. At present, 14.5 million borrowers — and the broader economy — are drowning in some $700 billion of negative equity.

The administration also believes federal and state officials could effectively pursue investigations of unexamined issues after a settlement. We doubt that. The government’s history on challenging banks and holding them accountable does not inspire confidence. And for banks — threatened by crushing legal challenges for their conduct — the whole point of settling is to restrict legal claims.

The proposed settlement reportedly would prevent the states from pursuing claims against banks relating to fraud or abuse in the origination of loans during the bubble. (In some states, the statute of limitations has expired for bringing challenges for faulty originations but not on all loans in all states.) It would also prevent states from pursuing claims for foreclosure abuses, like improper denial of loan modifications. And it would prevent them from pursuing banks’ misconduct in their dealings with the Mortgage Electronic Registration Systems database, or MERS, a land registry system implicated in bubble-era violations of tax, trust and property law.

The proposal would not preclude the states from pursuing the banks for wrongdoing in the repackaging and marketing of loans as mortgage-backed securities. But, as a practical matter, the ability to fully press such claims — and to achieve significant redress — could be impeded or blocked by the other constraints. Once one avenue of inquiry is closed off, it can be difficult to ascertain what happened along other points in the mortgage chain.

In effect, the legal waivers being contemplated would let the banks pay up to sweep wrongdoing under the rug.

For the settlement to be fair and meaningful, the redress from the banks must be far greater than the $25 billion that has been floated, or the release from legal liability far narrower. The best outcome would be for government officials to do what they should have done all along: develop the strongest possible legal case by fully investigating the banks’ conduct during the bubble and since the crash and then — and only then — talk settlement. In the meantime, the public is being well served by attorneys general who are willing to say that the deal currently on the table is not nearly good enough.