A year ago, President Obama declared that the use of chemical weapons by Syrian President Bashar Assad would cross a “red line for us” and might trigger a U.S. military response. Now, the president says it wasn’t his red line, but rather a line set by the international community and by Congress.

It’s true that the international community has long condemned the use of chemical weapons. And Congress in 2003 signed legislation specifically forbidding Syria from using chemical weapons.

But Obama plays down the importance of his “red line” comments a year ago by suggesting Congress and the world already had made similar pronouncements about military intervention. Neither the Chemical Weapons Convention nor the Syria Accountability Act authorizes the use of unilateral military force to enforce violations. And that’s the context of Obama’s original “red line” comment.

Obama’s revisitation of the “red line” statement came during a joint press conference with the Swedish prime minister in Stockholm, after Obama was asked whether “a strike [is] needed in order to preserve your credibility for when you set these sort of red lines?”

Obama responded that he wasn’t the one who set a red line, that it was a line set by the international community.

Obama, Sept. 4: First of all, I didn’t set a red line; the world set a red line. The world set a red line when governments representing 98 percent of the world’s population said the use of chemical weapons are abhorrent and passed a treaty forbidding their use even when countries are engaged in war. Congress set a red line when it ratified that treaty. Congress set a red line when it indicated that — in a piece of legislation titled the Syria Accountability Act — that some of the horrendous things that are happening on the ground there need to be answered for. And so when I said in a press conference that my calculus about what’s happening in Syria would be altered by the use of the chemical weapons, which the overwhelming consensus of humanity says is wrong, that wasn’t something I just kind of made up. I didn’t pluck it out of thin air. There’s a reason for it.

Let’s revisit what Obama said in a press conference on Aug. 20, 2012, after he was asked whether he “envision[ed] using U.S. military” in Syria “if simply for nothing else, the safekeeping of the chemical weapons.”

Obama, Aug. 20, 2012: I have, at this point, not ordered military engagement in the situation. But the point that you made about chemical and biological weapons is critical. That’s an issue that doesn’t just concern Syria; it concerns our close allies in the region, including Israel. It concerns us. We cannot have a situation where chemical or biological weapons are falling into the hands of the wrong people. 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. … We have communicated in no uncertain terms with every player in the region that that’s a red line for us and that there would be enormous consequences if we start seeing movement on the chemical weapons front or the use of chemical weapons. That would change my calculations significantly.

Twice, Obama referred to the use of chemical weapons as a red line “for us” — meaning the United States. And he was specifically answering a question asking about the possibility of military action.

In April, the White House sent letters from Miguel E. Rodriguez, assistant to the president and director of the Office of Legislative Affairs, to Sens. John McCain and Carl Levin, making clear the import of the president’s words. Rodriguez wrote: “Because of our concern about the deteriorating situation in Syria, the president has made it clear that the use of chemical weapons — or transfer of chemical weapons to terrorist groups — is a red line for the United States of America. The Obama administration has communicated that message publicly and privately to governments around the world, including the Assad regime.”

The White House later that day released the transcript of an ensuing conference call with an unnamed White House official, in part to explain the letter.

White House official, April 25: We go on to reaffirm that the President has set a clear red line as it relates to the United States that the use of chemical weapons or the transfer of chemical weapons to terrorist groups is a red line that is not acceptable to us, nor should it be to the international community. It’s precisely because we take this red line so seriously that we believe there is an obligation to fully investigate any and all evidence of chemical weapons use within Syria…. But I think nobody should have any mistake about what our red line is. It is when we firmly establish that there has been chemical weapons use within Syria, that is not acceptable to the United States, nor is the transfer of chemical weapons to terrorist organizations. And the people in Syria and the Assad regime should know that the President means what he says when he set that red line. And keep in mind, he is the one who laid down that marker. He’s the one who directed that we provide this information to the public. And he’s the one who directed that we do everything we can to further investigate this information so that we can establish in credible, corroborated, factual basis what exactly took place.

On Sept. 4 in Sweden, Obama was again responding to a question about a red line that would trigger a “strike.” Obama cited the Chemical Weapons Convention and the Syria Accountability Act — both of which prohibit the use of chemical weapons, which one could certainly argue are red lines — but neither one authorizes a unilateral military response.

The Chemical Weapons Convention, which Syria did not sign, prohibits the use of chemical weapons. It is signed by countries representing 98 percent of the world’s population and is considered “customary international law,” said Amy Smithson, senior fellow at the James Martin Center for Nonproliferation Studies. Smithson said she understood the president’s sentiment and agreed that “there is a red line drawn with the international community.” She said she was glad to see Obama make this larger reference.

Smithson also noted that in 1968, Syria acceded to the 1925 Geneva Protocol, which bans the use of chemical and biological weapons.

“Those treaties are the bulwark of international law,” she said.

But the Chemical Weapons Convention does not spell out the consequences for violations. Rather, it states that in “cases of particular gravity,” the issue should be brought by convention states to the attention of the United Nations General Assembly and the United Nations Security Council (see page 39). It is unlikely that the U.N. would agree to military strikes as both Russia and China have repeatedly used their veto power to block action against Assad’s regime. Moreover, U.N. Secretary-General Ban Ki-moon has warned that any “punitive” action taken against Syria might lead to “further bloodshed” and hinder “political resolution of the conflict.” He also condemned a unilateral attack.

“As I have repeatedly said, the Security Council has primary responsibility for international peace and security,” Ban said at a news conference. “The use of force is lawful only when in exercise of self-defense in accordance with Article 51 of the United Nations Charter and or when the Security Council approves such action.”

As for the Syria Accountability Act (more formally the Syria Accountability and Lebanese Sovereignty Restoration Act of 2003), it states that Syria must “cease the development and production of biological and chemical weapons.” It lays out a number of economic sanctions for violations, but does not speak to military enforcement. So it may be a red line, but not a red line that authorizes military action.

Obama is correct to argue that the international community has long drawn a “red line” condemning the use of chemical weapons, but his point blurs the fact that his “red line” comment in August 2012 was made in the context of what it might take for the U.S. to get involved militarily in Syria. While Obama may have had some justification for drawing that line based on international conventions, the decision to tie U.S. military involvement to Assad using chemical weapons was Obama’s red line.

— Robert Farley