Four reasons emerge after over a month of dissimulation, backtracking, and blame-gaming.
1. The Libyan intervention was to be preserved in amber as an ideal response, albeit one never to be repeated, given the shunning of the U.S. Congress in favor of the Arab League and U.N., the weird pride in “leading from behind,” and the disintegration of the post-Qaddafi state. Any sense that Libya had proven a haven for terrorists and was becoming as bad or worse as it was under Qaddafi could not be part of the pre-election narrative. Libya had to be forever frozen in time as if things had ended in 2011.
2. The idea of a bigoted, intolerant filmmaker was too good to let pass, and his arrest and demonization fed into a larger narrative of Obama as post-national, multicultural healer. By showcasing U.S. outrage against such a prejudiced provocateur, Obama and his team might again proclaim to the Arab world the themes of the Cairo Speech, and project the image of Obama and a new U.S. at the vanguard of Islamic anti-defamation.
3. If the crown jewels of the Obama foreign policy — al-Qaeda rendered impotent by the death of bin Laden, and Libya as the ideal finessing of the Arab Spring — were imperiled, then the entire administration policy in the Middle East might come under renewed scrutiny, from Iran to Syria to the Muslim Brotherhood in Egypt to the failure to identify Islamism as the enemy in a real, but unspoken, war on terror.
4. Obama could not tolerate the image of incompetence and laxity that arose immediately after the catastrophe; there was the need to insist that Libya was still viable and the death of a U.S. ambassador and three other Americans were attributable not to incompetence but to the uncontrollable excesses of bigots in the U.S. Libya could not resemble the widely criticized “Pottery Barn” state of 2004–08 Iraq. Any notion of PC softness was fatal to the image of a muscular Obama who was to be cast as tough by the fact that he was “wiser” and used “smart” power. Libya as a mess from an incompetent administration fed into the Carteresque narrative of this administration in the Middle East, one energized by the similarities of 1980 to 2012, both electoral and in matters of foreign policy.
Add it all up, and if there was not a cover-up, you would have to invent one.