CHARLOTTE — The Obama campaign is promising that the Democratic National Convention that kicks off Tuesday night will have a more positive tone than the Republican National Convention that convened in Tampa last week.

“What you saw out of Republicans last week was really baseless attacks on the president,” Obama campaign communications director, Brent Colburn, said during a briefing here. “It seemed like their priority was to tear down the president instead of putting up a positive vision and a positive case to the American people for why Mitt Romney should be elected president. Here, in Charlotte, you’re going to hear obviously the contrast between the two parties and between the two candidates, but it’s going to be more substance based. We’re really going to walk through some of the differences in philosophies, differences in plans and differences in the impact of those plans on middle class voters and on the American people in general.”