Mrs. Whitman's response, an average $600 rebate for homeowners, is politically understandable.

Mr. McGreevey said he supported doubling the size of the average rebate.

The Homestead program, for low- and moderate-income elderly and disabled people, paid an average rebate of about $350.

The plan the Democrats announced yesterday would restore the rebates to those making $100,000 to $200,000 a year but would cut the average rebate to $300.

The average rebate was $565 in the quarter, down from $720 a year earlier.

In the first quarter this year, the average rebate was only $15 more, or $565.

The No. 2 auto maker also said its average rebate for a car dropped to $1,000, from $1,150 in the fourth quarter of last year.

The average rebate, 13s 9d, amounted to one third of the average rent.

Under the proposal, tenants would receive average rebates of $20 this year, increasing to $100 by the fifth year, Whitman administration officials said.

Partly as a result, G.M.'s average rebate and other buying incentives rose to $860 a vehicle from $598 a year earlier.