To close the gap, Mr. Weicker wants a single-rate tax on personal income of 6 percent, reductions in other taxes and spending cuts of $1.2 billion.

Republicans also hope to use the issue as a springboard to scrapping the entire income-tax system and replacing it with a single-rate flat tax, a national sales tax or some other alternative.

Since the mid-1980's, the closest thing to a national discussion of a new tax system came in 1996, when Steve Forbes made a single-rate flat tax the centerpiece of his candidacy for the Republican presidential nomination.

But the vote gave Republicans a boost in their efforts to build support for alternatives to the progressive income tax: a single-rate flat tax, perhaps, or a national sales tax.

But he has not endorsed a single-rate tax and has said he will have a more detailed tax proposal before the year's end.

Are we for a single-rate flat tax?

Aides said he would appoint a bipartisan commission by the end of the year to explore all the ideas on the table, including a single-rate flat tax and a national sales tax.

From the right, Steve Forbes attacked Mr. Bush's plan as too timid and reiterated his support for replacing the entire income tax system with a single-rate flat tax.

Mr. Bush said he supported keeping the mortgage interest deduction, which would be eliminated under some proposals for a single-rate flat tax or a shift to a consumption tax.

When asked if they would prefer replacing the current graduated income tax with a single-rate flat tax, 43.5 percent of delegates in the pre-deliberation poll favored it and 43 percent opposed it.