There are widespread reports that President Obama had not fully appreciated the political consequences of responding to a question at an August press conference that asked about the consequences of the use of chemical weapons by the Assad regime. Obama replied that such a use would be to cross "a red line". Such an assertion was widely understood to be a threat either to launch air strikes or to provide rebel forces with major direct military assistance, including weaponry.
There have been sketchy reports that Syria did make some use of chemical weapons, as well as allegations that the reported use was "a false flag" operation, designed to call Obama's bluff. As the New York Times notes in a front page story on May 7, Obama "finds himself in a geopolitical box, his credibility at stake with frustratingly few good option".
Such a policy dilemma raises tactical issues of how to intervene without risking serious involvement in yet another Middle Eastern war. It also raises delicate questions of presidential leadership in a highly polarised domestic political atmosphere, readily exploited by belligerent Republican politicians backed by a rabid media that always seem to be pushing Obama to pursue a more muscular foreign policy in support of America's global interests.
Debate on Syria: 'Missing red line'
What is missing from the debate on Syria, and generally from the challenge to foreign policy, is a more fundamental red line that the US at another time and place took the lead in formulating - namely, the prohibition of the use of international force by states other than in cases of self-defence against a prior armed attack.
This prohibition was the core idea embodied in the United Nations Charter, and it was also consistent with the prosecution and punishment of surviving German and Japanese leaders after World War II for their role in "Crimes against Peace", that is, aggressive warfare. The only lawful exception to this prohibition was use of force in accord with a prior authorisation given by the UN Security Council.
The key hope for world peace was this consensus among the winners in World War II that in the future aggressive war and acquisition of territory by force must be outlawed. This happened in the Gulf War of 1991 and again in the NATO Libya War of 2011, but in each instance there were problems with whether the military operations exceeded the UN mandate.
Actually the Charter red line has been surprisingly well respected over the period since 1945, at least in clear instances of border-crossing sustained violence. The UN authorised the defence of South Korea in response to an armed attack by North Korea in 1950.
It even exerted effective pressure in 1956 on the United Kingdom, France and Israel to withdraw from territory seized after their attack on Egypt, and then in 1991 the UN successfully restored sovereignty to Kuwait in response to Iraq's aggressive occupation and annexation of the country.
The UN red line held up reasonably well until the end of the last century, although all along its interpretation was subject to geopolitical manipulation by reference to a variety of loopholes associated with claims of humanitarian intervention or a variety of strategically motivated covert interventions (for example, Iran in 1953 and Guatemala in 1954).
This pattern of evasion was a prominent feature of the Cold War as both sides intervened in foreign states or in their respective spheres of influence to uphold their ideological alignment with one or the other superpower. Such uses of international force without engaging the UN framework definitely eroded the authority of the anti-aggression red line and its stature in international law, but it did not produce any call for its abandonment.
What weakened this red line even more decisively was undoubtedly the US-led coalition of the willing attack on Iraq in 2003 after an American plea for UN permission had been rebuffed by the Security Council despite a concerted effort to convince its members that Iraq's supposed possession of weapons of mass destruction was a menace to the peace.
Iraq War: Death of the UN?
The undisguised defiance of this most fundamental red line of international law by the US also defied world public opinion that had expressed itself in the most massive anti-war demonstrations in all of history held in some 80 countries on February 15, 2003, a little more than a month before the "shock and awe" start of the Iraq War.
Richard Perle, often touted as the most astute of the neocon intellectuals who fashioned American strategic policy during the Bush years, was exultant about this breach of the red line, celebrating American aggression against Iraq in a Guardian article provocatively headlined, "Thank God for the Death of the UN".
Although the authority of the UN was definitely flaunted by the invasion and occupation of Iraq, the UN is far from dead as an organisation addressing the concerns of the world, and even its red line, although covered with dust, has not yet been erased.
What is baffling about the Obama approach is that it purports to be very mindful of the importance of exhibiting respect for international law. Just last September, in a speech to the General Assembly, Obama said: "We know from painful experience that the path to security prosperity does not lie outside the boundaries of international law." In his Second Inaugural, Obama repeated the sentiment: "We will defend our people and uphold values through strength of arms and rule of law."
And in arguing on behalf of taking collective action against states that violate international law told the Nobel Peace Prize audience in Stockholm, he said: "[t]hose that claim respect for international law cannot avert their eyes when those laws are flouted."
Yet, when reflecting on intervening in Syria or resort to a military option in relation to Iran's nuclear programme, Obama is silent about the relevance of international law, although neither instance of contemplated uses of force can be remotely claimed to be justified as either individual or collective self-defence.
For obvious reasons, there is also no mention of circumventing the red line by failing to seek authorisation from the Security Council. Presumably, since approval would not be forthcoming due to the anticipated opposition of Russia and China, it was not even worth considering in public.
It is true that the Clinton presidency in participating via NATO in the Kosovo War proceeded also to embark on a non-defensive war without authorisation for somewhat similar reasons as any resolution proposing use of force was sure to be vetoed by Russia and China. The Kosovo precedent evoked concern, but also a sense of achievement.
The Kosovo undertaking was justified at the time on moral grounds of imminent genocide, on political grounds as enjoying support from almost all of Kosovo's European neighbours and as being militarily feasible at a reasonable cost and productive of zero casualties among the intervening forces, and on historical grounds as having been perceived as generally beneficial to the threatened population.
In effect, the legitimacy of the war was allowed to offset the absence of legality.
Redrawing the red lines
The question raised is whether from an overall perspective, the red line of international law at stake in Syria is more like Iraq or Kosovo/Libya. It is unlike Iraq in the sense that there is an ongoing unresolved civil war that is actively destabilising the region, severe "Crimes Against Humanity" are being committed by the regime, and no end of the violence is in sight give the relative strength of the two sides.
It is, however, unlike Kosovo/Libya as there are proxy participants on both sides, the Damascus regime despite its behaviour maintains considerable internal support while the opposition is viewed with deep suspicion as to its democratic credentials, its inclusiveness and its respect for minorities.
In a sense, each conflict must be assessed within its own context, which should raise for discussion whether the red lines of international law and UN authority should be crossed in this instance on behalf of the blue lines of legitimacy (saving a vulnerable people from a humanitarian catastrophe) and white lines of feasibility (likelihood of success with minimum loss of life and high probability of positive net effects).
Finally, it can be argued that the changing nature of conflict has made the red line embedded in the UN Charter obsolete, given the kind of terrorist attacks since 9/11 leading to the global "war on terror" waged on a battlefield without national limits and increasingly doing the killing via robotic warfare.
Ideas of deterrence, containment and defence seem almost irrelevant in relation to security polity when the perceived assailants are individuals operating in non-territorial networks and exhibiting a readiness to die to complete the mission. As matters are proceeding, the policy about force is being formulated without bothering with the red lines of international law and the UN, giving us back the world of unregulated sovereign states and extremist non-states essentially deciding on their own when war is permissible.
Such normative chaos in a world where already nine countries possess nuclear weapons seems like a prescription for species suicide. Never has the world more needed red lines that are drawn by major states, and upheld by them out of the realisation that the national interest has also merged with the global interest.
What is strange is that Obama talks the talk, but seems unwilling to walk the walk. Such a disjunction invites cynicism about law and morality and induces despair on the part of those of us who believe the world we inhabit badly needs red lines, but the right red lines.
Redrawing the red lines that fit the realities of our world and keep alive hopes for peace and justice should be the great diplomatic undertaking of our time, the visionary projects of leading diplomats whose imaginative gaze extends beyond addressing immediate threats. The old red lines have been cast aside in contemplating what to do in relation to Syria, but without trying to establish new red lines that can serve humanity well in our disorienting century.
Richard Falk is Albert G Milbank Professor Emeritus of International Law at Princeton University and Visiting Distinguished Professor in Global and International Studies at the University of California, Santa Barbara.
The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.