Who With the official kick-off of President Barack Obama's re-election campaign this weekend in Ohio, it's clearly time to test out a few attack lines on Republican opponent Mitt Romney. Think of it as the start of a boxing match. In the blue corner, Team Obama is trotting out to the centre of the ring and throwing a few jabs just to see what sticks to Romney's square-cut chin. What This is a slick 30-second TV spot of a kind we are going to be seeing a lot of this year. As such, it has to pack a lot in...