WASHINGTON -- Al Gore is casting the election as a choice between prosperity and ''a massive tax on America's potential,'' pitching debt reduction as his economic priority.

Paying down the national debt in 12 years, as he hopes to do, would eliminate interest payments that form essentially the government's third largest program behind Social Security and defense, the Democratic presidential candidate told the Brookings Institution.

Gore switched his focus Thursday from pummeling Republican presidential rival George W. Bush on Medicare.

''Forty days from now, prosperity itself will be on the ballot,'' Gore said. He said Bush's across-the-board tax cuts would disproportionately benefit the wealthy, giving ''too much to too few at the expense of too many.''

By taking money from programs and debt reduction, he said, Bush would tax America's potential.

Both Bush and Gore say they are not overspending projected surpluses and are accounting accurately for their proposed tax-cut spending. Independent analysts say that claim is questionable on both sides.

Gore is using the nation's roaring economy to sell himself as the man who will keep things humming along. ''We cannot let this opportunity slip through our hands,'' he said Thursday after the government reported that the economy grew more quickly during the spring than first estimated.

''We have to ask the hard questions about what is right for our economy and our families,'' he said in his speech. ''We have come a long way these last eight years but I am not satisfied.''

Gore said he would pay $2 of projected surpluses toward debt reduction for every $1 he would devote to tax cuts or investments.

Bush, he said, would give $667 billion of the surplus to the wealthiest 1 percent of the population in tax cuts. Gore maintained that is greater than the amount Bush would spend on education, health care, prescription drugs and national defense combined.

Polls indicated that Gore is more trusted than Bush on the issue of the economy, as the Democrat is on most of the top issues.

Gore said his campaign will cut taxes for middle-class families that need it the most, invest in health care, education, a clean environment and a secure retirement. He would set aside a portion of the surplus in a reserve fund in case of an economic downturn.

Elimination of the debt would cut a major use of government money and reduce government spending to its lowest level in 50 years, Gore said.

The Democrat's address came as new statistics were released highlighting the accomplishments of the past eight years.

The poverty rate in America dipped last year to 11.8 percent, the lowest point in 21 years, while median household incomes reached a record high, new Census Bureau data released this week showed.

''The biggest threat to the economy and the continued prosperity would be a giant tax cut mainly for the wealthy that would put us back into deficits again,'' Gore said.

At a Democratic fund-raiser Wednesday night, Gore ridiculed Bush's claim that the country was in better shape in 1992, before Gore and Bill Clinton took office.

''My opponent likes to say we were a whole lot better off eight years ago,'' Gore said as the partisan Democratic crowd groaned. ''That was my reaction,'' Gore responded to laughter.

He cited the $300 billion deficit that is now a projected $268 billion surplus for next year.

''Witness the new results today with poverty going down again mostly in inner cities with median family income rising above $40,000 for the first time. This is a great set of results but it's not good enough. And in order to make it even better we have to keep the fundamentals right.''

Advisers hoped Thursday's speech would also serve as a framework for Gore's priorities headed into the debates beginning next Tuesday.