The two main “blame the Administration” arguments are that they held up the military response to the attack and that they could have better fortified the mission in anticipation of some kind of attack given the chaos in Libya after Qaddafi’s fall.
According to a report produced by the Republican majority on the House Armed Services Committee, the first charge is flatly false. Administration officials, according to Congressional Republicans, “placed no limitations on the military’s immediate reaction to the attack.” In fact, Joint Chiefs Chairman Martin Dempsey told the committee that “the President instructed us to use all available assets to respond to the attacks to ensure the safety of US personnel in Libya.” And the evidence is very clear that the military, in fact, committed every immediately available asset to Benghazi.
The second claim has real merit, though blame would fall more on the State Department hierarchy than on top Administration officials. Several intelligence agencies and Ambassador Stevens himself warned that the security situation in Benghazi was deteriorating and that jihadi groups were concentrating there.
The bipartisan Senate Intelligence Committee report ”found the attacks were preventable, based on extensive intelligence reporting on the terrorist activity in Libya — to include prior threats and attacks against Western targets — and given the known security shortfalls at the US Mission.” The report focuses much of the blame on the State Department, suggesting its officials in charge of diplomatic security should have followed the CIA’s lead and fortified its Benghazi outpost.
In response, the administration and its defenders often note that House Republicans repeatedly cut hundreds of millions of dollars in funding for diplomatic security in the two years before the attack. Moreover, two of the four people killed during the attack were defending the CIA annex about a mile away from the mission, and American personnel were also forced to withdraw from that more heavily fortified annex.
In short: counterfactuals are always hard, so it’s tough to say whether or not the State Department could have stopped this specific attack had it better fortified the mission or been better funded.