Here’s a look at some of the most important events that have taken place in the time since the red-line was first put into place:
Aug. 20, 2012: President Obama during a speech on the threat of weapons of mass-destruction warns against chemical weapons’ use in Syria, for the first time setting the U.S.’ red-line against such a move. “That would change my calculus,” he said. “That would change my equation.” The warning serves as the first U.S. threat of intervention in the conflict through military means, at a time when it is becoming more obvious that the civil war would be lengthy.
Dec. 3, 2012: Obama repeats his warning to Assad in a speech at the National Defense University, saying “The use of chemical weapons is and would be totally unacceptable. And if you make the tragic mistake of using these weapons, there will be consequences and you will be held accountable.”
Mar. 19, 2013: Syria claims that rebel fighters used chemical weapons against government forces during fighting outside of Aleppo, killing 26 people including government soldiers. To add credibility to their claim, Damascus writes to United Nations Secretary-General Ban Ki-Moon to send in a team of investigators to confirm. The Syrian oppositions denies the regime’s claims, saying the weapons were actually unleashed against them, echoing the call for an investigation.
Apr. 18: Britain and France provide letters to the United Nations claiming possession of evidence that chemical weapons have been utilized multiple times in the time since December, including in and around the cities of Aleppo, Homs and possibly Damascus.
Apr. 23: An Israeli official says that they are convinced that chemical weapons have been used in Syria; Prime Minister Benjamin Netanyahu, however, declines to back up the statement.
Apr. 25: Secretary of Defense Chuck Hagel and Secretary of State John Kerry each say that evidence exists that chemical weapons have been used. In a letter to Congress, the administration claims that they possess “physiological evidence,” opposed to photographic proof, from the sites.
May 2: Turkish Prime Minister Recep Tayyip Erdogan tells Japanese media that it is “clear that the Assad regime” is using chemical weapons.
Jun. 5: France says that it is now “certain” that the Syrian government used sarin gas in multiple attacks against civilians.
Jun. 13: The Obama administration finally says that it has confirmed that the Syrian government used chemical weapons against civilians. According to a statement from the White House, the intelligence community with a high-degree of confidence “estimates that 100 to 150 people have died from detected chemical weapons attacks.”
Jun. 18: The Group of 8 (G8) — which consists of the United States, United Kingdom, France, Germany, Italy, Canada, Japan, and Russia — issue a statement in which they “condemn in the strongest terms any use of chemical weapons and all human rights violations in Syria.” The document refrains, however, from assigning blame for their use.
Jul. 10: Russian U.N. Ambassador Vitaly Churkin says that Russia’s scientists dispute the findings of Western intelligence agencies, instead claiming that it was the rebels who launched the assault using a “homemade rocket.”
Aug. 18: The requested team of U.N. weapons inspectors finally gains entrance into Syria, after a lengthy negotiation process that severely limits the scope of their investigation.
Aug. 21: Israeli intelligence indicates that “certain types of chemical weapons were moved in advance to the same Damascus suburbs where the attack allegedly took place a week ago,” according to the Wall Street Journal. The CIA was reportedly able to verify this evidence.
Aug. 21: Videos begin to surface showing hundreds of men, women, and children suffering from convulsions and other signs of a mass poisoning. Opposition groups claim that hundreds of civilians have suffered from a chemical weapons attack at the hands of the Syrian government.
Aug. 21: Foreign Policy reports that the U.S. intercepted “panicked phone calls” from an official at the Syrian Ministry of Defense to a leader of a chemical weapons unit in the hours after the attack, “demanding answers for a nerve agent strike.”
Aug. 21: Obama administration officials begin making calls to their foreign counterparts, discussing how to respond to the possible chemical attack. Over the next few days, according to a list from the White House, U.N. Ambassador Samantha Power alone takes part in thirty calls. President Obama personally speaks with the leaders of the United Kingdom, France, Australia, and Canada in that time.
Aug. 22: France urges a military response to Syrian chemical weapons usage.
Aug. 22: Israel agrees publicly that chemical weapons were launched in Syria. “According to our intelligence assessments there was use of chemical weapons,” said Israeli minister of strategic and intelligence affairs and international relations, Yuval Steinitz, “and this of course was not for the first time.”
Aug. 22: Russian Foreign Ministry spokesman Aleksandr Lukashevich suggests it was in fact the rebels who used chemical weapons as part of a “a provocation planned in advance.” “It draws attention to the fact that biased regional media have immediately, as if on command, begun an aggressive information attack, laying all the responsibility on the government,” Lukashevich said in a statement.
Aug. 23: President Obama urges caution in the face of initial reports out of Syria, calling the allegations ““very troublesome.” “What we’ve seen indicates clearly this is a big event, of grave concern,” Obama said. While the president said the situation is “going to require American attention,” he stopped short of calling for any military response.
Aug. 23: Syrian rebels claim that a network of defectors managed to smuggle at least three victims of the alleged assault out of Syria and into Jordan to provide blood samples as evidence.
Aug. 24: Doctors Without Borders says in a press release that associated networks had treated 3,000 victims showing signs of toxicological poisoning and at least three hundred dead.
U.S. Moves Towards Military Response
Aug. 24: Rep. Justin Amash (R-MI) comes out as one of the strongest voices against potential military action against Syria without Congressional approval, taking to Twitter to warn of the unconstitutionality of any such decision.
Aug. 24: U.S. moves naval warships in the Mediterranean Sea to allow for a range of possible American military responses, including launching Tomahawk cruise missiles in retribution for the use of chemical weapons.
Aug. 25: American officials shift their tone regarding Syria, with one calling Damascus’ sudden pledge to allow unhindered access to the attack site to U.N. inspectors “too late to be credible.”
Aug. 25: Sen. Bob Corker (R-TN) and Rep. Eliot Engel (D-NY), ranking members of the Senate Foreign Relations and House Foreign Affairs committees respectively, both come out in favor of the U.S. using force to punish Assad for using chemical weapons.
Aug. 26: Russian President Vladimir Putin tells British Prime Minister David Cameron that no evidence exists that the most recent chemical weapons attack ever happened.
Aug. 26: Secretary Kerry in a statement at the State Department press briefing calls Syrian chemical weapons use a “moral obscenity,” laying the blame on the shoulders of Assad’s government. Kerry also pushes back on claims no attack occurred, saying “Anyone who can claim an attack of this staggering scale can be contrived or fabricated needs to check their conscience and their own moral compass.”
Aug. 26: Sen. John McCain (R-AZ) — long an opponent of the administration’s Syria policy — tells The Daily Beast that in not striking Assad earlier, Obama basically allowed last week’s attack. “[Syria] viewed that not as a red line but as a green light, and they acted accordingly,” McCain said.
Aug. 27: Sen. Corker tells Fox News on Tuesday that he believes that the administration has fulfilled the requirements of the War Powers Resolution in consulting Congress. Several lawmakers disagree, having signed on to a letter to Obama demanding that he call Congress back into session so that they can vote on any proposed military action.
Aug. 27: The League of Arab States issues a statement casting the blame for using chemical weapons on the Syrian government, but coming short of condoning the U.S.’ move to punish Assad. Instead, the Arab League calls for the United Nations Security Council to clear any use of force.
Aug. 27: Vice President Joe Biden in a speech became the highest ranking administration official label the Assad regime as the perpetrator of the last week’s attack. “There is no doubt who is responsible for this heinous use of chemical weapons in Syria: The Syrian regime,” he said.
Aug. 28: The United Kingdom announces its intention to seek a U.N. Security Council resolution approving the use of force against Syria, holding morning consultations with the other members of the P-5 — the United States, China, Russia, and France. Any one of the five members can veto any U.N. resolution, which is likely in the case of Russia and China.
Aug. 28: NATO Secretary-General Anders Fogh Rassmussen issues a statement saying that evidence points to the Syrian government being responsible for the use of chemical weapons, saying that the action is “unacceptable and cannot go unanswered.” “This is a clear breach of long-standing international norms and practice… those responsible must be held accountable,” Rasmussen added.