Where's the option "The guy who pulled the trigger"?
Actually, there is a convoluted reasoning that brings Romney into the equation. We know the killing (I still haven't seen a body) of bin Laden was purely political. In fact, bin Laden was collateral damage in the politics at hand.
The political purpose for the killing was to re-elect that Obamo character. If that Obamo character did not have to campaign, the killing would not have been necessary. So, Romney, even before he or we knew he was involved in this inevitable presidential campaign season, played a major part (in absentee) in the decision to kill bin Laden.