As he contemplates the American response to Syria's gas attack, President Obama has made it clear that he is consulting international law. What can he do that fits within international law? And what might he do outside of it?
International law forbids the use of force by one country against another. This is a commitment that all countries have accepted. It forms the constitutional underpinning of the modern international order and has a central place in the United Nations Charter. The use of force is only legal if authorized by the Security Council or taken in self-defense.
The first path for the Obama administration is to ask the Security Council for a mandate to intervene. Regarding Libya in 2011, the Council voted to authorize the use of force to defend the Libyan people against the violence of the Qaddafi government. Qaddafi had few supporters among governments around the world and it was relatively easy to form a consensus against him.
In Syria, the diplomatic situation is different. Russia is eager to preserve President Bashar Assad's government. China opposes intervention and favors a negotiated settlement between Assad and his opponents. If Russia and China refuse to allow the Council to authorize military attacks, then the U.S. and others will face the decision of going it alone.
There are precedents for military action without the United Nations, some positive and some negative. George W. Bush's invasion of Iraq in 2003 highlights mistakes that should be avoided at all costs: a faked rationale for the war, false evidence of weapons of mass destruction, a broad and powerful international coalition against the attack, a full-scale American invasion and occupation and no real plan for the aftermath of the invasion Together these made for the biggest American foreign policy disaster since the Vietnam War.
A more promising example is the Kosovo bombing campaign. In 1999, NATO bombed Yugoslavia for almost three months to prevent it doing more harm in Kosovo. Without U.N. endorsement, NATO was left to claim that its action was morally and politically right, even if legally suspect.
The campaign caused a great deal of destruction in Yugoslavia, but arguably it contributed to ending the Yugoslav wars and Milosovic's atrocities in Kosovo. This compares favorably to the failure to intervene in Rwanda in 1994 to stop the genocide there. Compared to Rwanda, Samantha Power, now the U.S. Ambassador to the U.N., has said that the Kosovo operation represents a victory for the "upstanders" over the "bystanders" when human rights are at stake.
With Kosovo and Rwanda in mind, a consensus is building that it may be lawful to use military force in defense of human rights without violating international law. This is known as the "responsibility to protect" (R2P). Many of Obama's advisors, including Samantha Power, have contributed to its development and it is likely that Obama takes it seriously. On this view, a government that commits mass human rights crimes loses its right to govern, and the international community has a responsibility to intervene to protect the people. The Syrian government would qualify, even before its chemical massacre last week.
The problem is that this R2P approach contradicts the basic law in the U.N. Charter that bans the use of force. One permits what the other forbids. One rests on black-letter law, the other on what some governments say about the law. How can these be reconciled?
Russia and China reconcile them by asserting that the recent move toward humanitarian intervention is unacceptable if it violates the U.N. Charter. This reinforces the old law against the new innovation. It also prevents taking action against the Syrian government without the approval of Russia and China in the Security Council.
The Obama administration appears to be moving toward a different conclusion: as more countries accept the notion of international humanitarian intervention, they are making an informal amendment to the laws that are written in the U.N. Charter. This isn't the first time that new developments have overtaken old rules: in the 18th century, a country's "territorial water" was said to extend "as far as a cannon will carry" (about three nautical miles). By the 20th century, many countries were making larger claims over the high seas, and gradually the line was extended to its present distance of 12 nautical miles from shore.