WHEN politicians bashed Wall Street for its reckless mortgage lending in the wake of the subprime crisis, bankers retorted that it was the politicians’ enthusiasm for expanding home ownership, even if it meant small deposits and low credit standards, that had really fomented the disaster. Yet that enthusiasm is undimmed: in a speech on October 20th Mel Watt, head of the Federal Housing Finance Authority (FHFA), announced plans to reintroduce mortgages with deposits as low as 3% through Fannie Mae and Freddie Mac, the two government-backed housing giants it regulates.

Both Fannie and Freddie were bailed out during the financial crisis. There was much talk in Congress of winding them down; in the meantime, they tightened loan requirements to limit the risk to taxpayers. But that changed when Barack Obama appointed Mr Watt, a congressman from North Carolina and long-term evangelist for home ownership.

Fannie and Freddie do not issue mortgages. Instead, they buy them from banks and guarantee the securities into which they are bundled for resale. Over the past two years many big mortgage lenders have paid billions of dollars in fines and been forced to buy back piles of dud loans on the grounds that they did not conform to Fannie’s and Freddie’s rules. These settlements were controversial, in that the pair had actively sought out risky mortgages to satisfy their mission to promote “affordable housing”.

In response, many banks have stopped lending to riskier borrowers. The new rules announced by Mr Watt are supposed to entice them to resume by narrowing the circumstances under which they can be held at fault. The banks, which hold buckets of surplus deposits and are eager for safe ways to deploy them, are pleased, since the risks of making loans with low deposits will once again rest with Fannie and Freddie.

This week a consortium of federal agencies also announced new standards that would permit banks to securitise and sell mortgages without retaining a 5% stake—leaving them little incentive to maintain high lending standards. In 2011 these agencies had suggested that such securities should only include mortgages with a minimum deposit of 20% and monthly repayments of no more than 35% of the borrower’s income. In the end they raised the loan-to-income ratio to 43% and dropped the minimum deposit entirely. The reason for the weaker standard, they said, was the concern that “additional constraints on mortgage-credit availability” might “disproportionately affect LMI (low-to-moderate-income), minority or first-time homebuyers.” Whether the lack of constraints might disproportionately affect taxpayers, the regulators did not say.