DENVER (AP) — Republican Rep. Cory Gardner of Colorado says Vice President Joe Biden's comment that the middle class has been "buried" during the past four years is a "tremendous acknowledgment" of the Obama administration's record.

Biden made his comment Tuesday while arguing that Republican presidential candidate Mitt Romney would cut taxes for millionaires and raise them for middle-class families.

At an evening news conference arranged by Romney's campaign, Gardner said burying the middle class wasn't exactly the shovel-ready project Obama promised when promoting his stimulus plan to boost the economy.

Gardner said Biden's remark was a "significant setback" for President Barack Obama before the first presidential debate.

Obama and Romney debate Wednesday night at the University of Denver.