(fade from black to video of Mitt Romney)
"I'm Mitt Romney and I endorse President Obama for Re-Election"
(screen goes dark to reveal)
"See? Two can play that game"
(fade to black)
Is a much more simple counter-argument to make in a television advertisement to show everyone how duplicitous the Romney campaign has been in their own advertisements.
Simply edit tape of Romney to achieve the above outcome and put a flash-card message at the end.
Very simple and very effective.
IMHO.