I read an Article To-Day on this subject...
I was not aware how this was such a big issue...it seems to be widely talked about by U.S. politicians including John McCain, who said that if he was president, he would have already given all the assistance possible (e.g. satellite images, troops, supplies etc.), and would have already authorised an extra-judicial mission if the Nigerian authorities dragged their feet on the matter.
(I find it a little distasteful that the writer seems to be saying: "If we carried out a "secret" mission, we'd feel great about it, and about not bragging it"... it sounds like they're already bragging).
I personally think that if the Americans did this, I wouldn't really lose sleep over it. But my actual opinion would probably be that the Americans have been in two many extra-judicial things in recent years and that they should have devoted more time and resources to peacefully helping other countries. Maybe then it would be easier to acquiesce when such activities happen! ...and at the same time, maybe the actual country or a regional group of countries would then be better placed.