WASHINGTON — President Barack Obama is launching a tough new tax-equality pitch in a television advertisement asserting that Republican rival Mitt Romney's economic proposals would mean cuts for the wealthiest Americans and higher bills for everyone else.

The latest offensive comes as Obama and Romney take their respective election campaigns to three of the most contested states — Florida, Colorado and Virginia — and as a bitterly divided Congress pushes toward a summer recess with votes that center on front-burner issues like taxes and spending but which are mostly symbolic place-holders for November.

The Obama campaign ad, which will be aired in eight states including the two the president was visiting Thursday, cites a report by the nonpartisan Tax Policy Center that argues Romney has paid a lower proportion of his income in taxes than many people of lesser means. "He pays less, you pay more," the ad says.