Seven Times The White House Discussed The Syria Red Line Jim Watson / AFP / Getty Images U.S. Secretary of Defense Chuck Hagel speaks with reporters after meeting Egyptian President Mohamed Morsi and Egypt's Defence Minister in Cairo, on April 24, 2013. The White House confirmed Thursday that intelligence reports indicate "with varying degrees of confidence" that the Syrian regime has used the chemical weapon sarin, a possible sign that Syria has crossed President Barack Obama's "red line" that would change U.S. policy towards the war-torn country. Ever since August 2012, the Obama administration has defined the use or proliferation of chemical weapons as a game-changer that would be a "grave mistake" for the Assad government. But the "red line," and threat of a resulting response by the U.S., has never been clearly defined by the White House. Obama has qualified his statements by saying the red line would be crossed with "a whole bunch" of chemical weapons. He has also never explicitly promised a military response to the use of chemical weapons, though his administration's comments have suggested such a possibility. For now, the White House is only saying it will investigate further, and stay prepared. Obama is pressing now "for a comprehensive United Nations investigation that can credibly evaluate the evidence and establish what took place," according to a letter released Thursday from Miguel Rodriguez, the head of legislative affairs. Secretary of Defense Chuck Hagel, when asked today if a red line had been crossed, said, "We need all the facts." He added that the military would prepare a set of possible options for response depending on the outcome of policy decisions now before the President. With so much in flux, here is a look at the specific language used by Obama or his staff on six different occasions to warn Syria against the use of chemical weapons. President Barack Obama: Aug 20, 2012 We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. That would change my calculus. That would change my equation. Deputy Press Secretary Josh Earnest, Aug 21, 2012 So as the President said yesterday in terms of Syria, we're watching very closely the stockpile of Syrian chemical weapons; that any use or proliferation efforts related to those chemical weapons is something that would be very serious and it would be a grave mistake There are important international obligations that the Syrian regime must live up to in terms of the handling of their chemical weapons. And the officials who have that responsibility will be held accountable for their actions and will be held accountable for living up to those international obligations. Press Secretary Jay Carney: Dec. 14, 2012 The President addressed this very clearly from this podium what his views are on that matter, and they regard both the use of chemical weapons, the potential for use of chemical weapons by the Assad regime, as well as movement in the sense of proliferation of weapons of mass destruction like chemical weapons. I think our warnings about any consideration of the use of these weapons were extremely clear and stark. Our promise of significant consequences should the Assad regime go down that road were very clear and stark, and they remain in place. Vice President Joe Biden: March 4, 2013 Because we recognize the great danger Assad's chemical and biological arsenals pose to Israel and the United States, to the whole world, we've set a clear red line against the use or the transfer of the those weapons. President Barack Obama: March 21, 2013 I've made it clear to Bashar al-Assad and all who follow his orders: We will not tolerate the use of chemical weapons against the Syrianpeople, or the transfer of those weapons to terrorists. The world is watching; we will hold you accountable. Press Secretary Jay Carney: April 23, 2013 The President spoke very clearly about this from this podium and his views on the unacceptability of the use of chemical weapons. I'm not going to speculate about how they would be used. The use of chemical weapons would be unacceptable, as would the transmission or transference of chemical weapons to others outside of Syria or non-state actors. White House Official: April 25, 2013 It is absolutely the case the president's red line is the use of chemical weapons or the transfer of chemical weapons. Updated 1:33 with White House official's comments. Here is the White House letter to Sen. John McCain letter.