Mitt Romney is going after President Obama's foreign policy record, long considered a feather in Obama's cap, by attacking the administration's response to the Sept. 11 assault on the U.S. consulate in Benghazi that killed Chris Stevens, the U.S. ambassador to Libya, and three other Americans. Republicans first called the violence evidence that Obama's policy of trying to rebuild bridges with Muslim countries had made our enemies think we were weak. Now the Romney camp is suggesting that Obama tried to cover up evidence that this was a terrorist attack, rather than a protest against an anti-Islam film that spun out of control, so it won't disprove his claim that he's got al Qaeda on the ropes. How much has the White House's explanation of what happened changed since the attack? Here, a brief timeline: 

Sept. 11
Not long after 8 p.m. local time, demonstrators gather in front of the consulate in Benghazi to denounce the anti-Islam film, Innocence of Muslims, represented in the trailer posted online. Around 9:30 p.m., the attackers join the group and begin firing at the main building of the compound with guns and rocket-propelled grenades. Computer technician Sean Smith dies inside. Stevens is taken to a nearby hospital by Libyans, but dies of smoke inhalation. Two other Americans — security officers Tyrone Woods and Glen Doherty — are killed in a shootout after Americans seek refuge at another U.S. compound, only to be ambushed.

Sept. 12
U.S. intelligence agencies intercept calls between members of Ansar al-Sharia, the jihadist group suspected of carrying out the attack, and members of al Qaeda in the Islamic Maghreb (AQIM), the group's North African affiliate. The Libyans brag that, after watching riots on Sept. 11 at the U.S. embassy in Cairo, they had decided to go forward with an attack in Benghazi. Secretary of State Hillary Clinton says the killings were committed by "heavily armed militants." White House spokesman Jay Carney notes that the Benghazi turmoil was triggered by the "disgusting" anti-Islam movie trailer, but says "there is no justification at all for responding to this movie with violence." President Obama denounces what he calls an "outrageous and shocking attack," and adds that "no acts of terror will ever shake the resolve of this great nation... or eclipse the light of the values that we stand for."

Sept. 14
Carney denies reports that the U.S. knew that al Qaeda was planning an attack in Libya. "I have seen that report, and the story is absolutely wrong," he says. "We were not aware of any actionable intelligence indicating that an attack on the U.S. mission in Benghazi was planned or imminent. That report is false."

Sept. 16
Libyan President Mohamed Yusuf al-Magariaf says the Benghazi attack was clearly a "pre-planned act of terrorism." Susan Rice, the U.S. ambassador to the United Nations, says the Benghazi attack was a "spontaneous" attack that erupted in response to the anti-Islamic movie trailer. It wasn't, she says, a pre-planned terrorist attack. 

Sept. 19
Matt Olsen, the director of the National Counterterrorism Center, tells a congressional committee that the evidence suggests this was indeed "an opportunistic attack," not a planned assault. He says, however, that it could be considered terrorism, marking the first time anyone in the Obama administration has explicitly labeled it so.

Sept. 20
Carney, pressed on the question again, says it's "self-evident that what happened in Benghazi was a terrorist attack... Our embassy was attacked violently, and the result was four deaths of American officials. So, again, that's self-evident." Carney tells reporters that even though it appears the militants hadn't sketched out the assault in advance, it's reasonable to assume that the opportunity for the attack arose on the anniversary of the Sept. 11 terrorist attacks. "The attack occurred on Sept. 11, 2012," he says, "so we use the same calendar at the White House as you do." Obama says the administration is still investigating whether al Qaeda had a hand in sparking the protests, but it's clear that the outrage over the video was used as "an excuse by extremists" to launch the attack.

Sept. 26
Team Romney ramps up its criticism of Obama's response to the Libya violence, accusing him of a Watergate-style cover-up. "Amid Middle East turmoil and six weeks before the election, President Obama refuses to have an honest conversation with the American people," Reince Priebus, chairman of the Republican Party, writes at Real Clear Politics. "The country deserves honesty, not obfuscation, from our president."

Sept. 28
Rep. Peter King (R-N.Y.) says that U.N. Ambassador Susan Rice should resign over her suggestion that terrorists were not behind the attack. "She gave out information which was either intentionally or unintentionally misleading and wrong," says King, chairman of the House Homeland Security Committee, "and there should be consequences for that." Sen. John Kerry (D-Mass.), chairman of the Senate Foreign Relations Committee, defends Rice, saying he's "deeply disturbed by efforts to find the politics instead of finding the facts."

Sources: The Daily Beast, Daily Mail, Fox News, Politico (2), Real Clear Politics, The Washington Post