Washington ? The Bush administration is proposing to transform a cornerstone of the nation’s housing policy for the poor, replacing a federal program that provides rent vouchers to 2 million families with a system that would give broad new powers to local housing authorities.

The idea, which is intended partly to save money, is a sequel to the administration’s failed attempt a year ago to convert federal rent vouchers, the government’s largest form of housing subsidies, into block grants run by states. It would bypass states, giving lump-sum payments directly to the nation’s 3,000 public housing authorities.

This year’s version would eliminate a longstanding rule that families in the program, known as Section 8, pay no more than two-fifths of their income in rent. It would erase a requirement that three-quarters of the vouchers go to families who are extremely poor. And it would omit the federal quality standards that have covered all the apartments and houses in which participants live.

In his second attempt to redefine Section 8, President Bush has changed important details but kept the philosophy behind the plan that was quickly decried last year by lawmakers of both parties and by many affordable-housing and anti-poverty groups.

Like the first one, the new proposal would extend to housing policy central ideas behind the welfare overhaul of the 1990s: reduced federal control and efforts to lessen low-income people’s dependence on long-term public assistance. Like last year’s, the proposal would replace a government guarantee of a specified number of rent vouchers regardless of cost with a specific sum of money for housing authorities to stretch as far as they can.

Debate over the “Flexible Voucher Program,” mentioned in a few sentences in the budget Bush released in February, is in early stages in Congress, which would have to approve it.