President Obama's campaign is running a new tv ad in Colorado, claiming Governor Romney's policies would "hit the middle class harder."
The ad says Romney wants to extend tax cuts for millionaires at the expense of middle-income earners.
Romney has called for an extension of tax cuts first approved by former President George W. Bush for all income earners.
Obama wants to let the cuts expire at the end of the year for families making more than $250,000 a year. The ad says Romney doesn't see the "heavy load" the middle class is carrying.