NO, OBAMA IS NOT GOING TO LOSE THE ELECTION BECAUSE OF BENGHAZI
The Obama administration initially described the lethal attack on the U.S. diplomatic post in Benghazi as the result of a protest against the online Innocence of Muslims video; the administration now says it was a terrorist attack. Obama opponents want to make a big deal of the change in the administration's story (although Obama did use the phrase "act of terror" in an allusion to the attack the day after it occurred); they're not making much of an effort to conceal the fact that they're doing this for political gain in an election year, while accusing Team Obama of a cover-up (although if it was that, it was a short-lived one).
But sorry, Republicans -- this isn't going to get Mitt Romney elected. There are several reasons for that.
First of all, while Republicans think they're taking the high ground by accusing the administration of turning the Innocence of Muslims filmmakers into scapegoats, the Republicans are doing pretty much the same thing themselves: they're blaming the administration for the killings. At first they accused the administration of not placing the blame where it belongs -- on the actual killers. But they're deflecting blame away from the actual killers, too.
Now, there does seem to have been a failure to anticipate the attack and provide adequate security. (There's also plenty of unrest around the globe that actually can be ascribed to anger at that video, although it seems not to have played a part in the Benghazi killings.) But if Republicans are blaming the administration while the administration is blaming the actual killers, it's the administration that has the high ground.
The public has never been in the habit of blaming presidents for the actions of enemies overseas. George W. Bush is blamed for going into Iraq in search of WMDs that weren't there, and for allowing his two wars to become quagmires, but he's never really been blamed, except by lefties, for missing the signs that 9/11 was about to happen. And the Bush subordinate most associated with missed signals, Condoleezza "I Don't Think Anybody Could Have Predicted" Rice, still polls surprisingly well among non-Republicans as well as Republicans.
Americans didn't initially blame Jimmy Carter for the taking of the hostages in Iran in November 1979 -- in fact, his approval rating experienced a spike after that. (Americans were upset with Carter when the situation wasn't resolved, but not when it happened.)
And, of course, the current situation is "merely" the death of four overseas personnel -- most of America, frankly, won't spend too much time thinking about it, because it's not melodramatic like a long-term hostage situation, and it didn't happen in this country. Recall that after two U.S. embassies were bombed in Africa, President Clinton's retaliation efforts were seen by many as "wagging the dog" -- they didn't think the situation was a big deal that demanded a response.
Bill Clinton didn't suffer much at the polls either for having terrorist attacks take place on his watch or for failing to bring the perpetrators to justice. Yes, that was pre-9/11, but I think the key point was that it was happening overseas, to government professionals we citizens never got to know. Call that a cynical view, but that's how Americans see this sort of thing.