The 4th Estate Project says Barack Obama's campaign has successfully turned the debate over taxes into a negative for Romney. They broke down news coverage of the election and found that when newsmakers mentioned "taxes," 17% of those statements have been about a candidate's character - and 95% of those have been about Romney.
When they broke down the statements about "taxes" and "character," a little more than half have been neutral, but nearly 40% have been negative toward Romney.
Unsurprisingly, the newsmakers that are driving this negativity toward Romney are Obama and his staff. One-quarter of the statements negative to Romney about Character and include the word “tax” come from Obama and his staff. Citizens, academics, journalists, unaligned analysts and members of congress make up the remaining 75% of negativity. This data shows that the Obama campaign has done en excellent job of amplifying this issue and making it an issue across the media space among an assortment of newsmakers.

