The Assad regime in Syria deserves swift and severe chastisement if indeed it has used chemical weapons on its own people, as the United States government and its allies appear to have concluded after studying the evidence available.
A military attack, however, carries a very real risk of worsening an already violent conflict.
The "responsibility to protect" principle may have gained currency since the US-led Nato intervention helped end ethnic cleansing in Kosovo, but the much more complicated Syrian situation presents daunting practical obstacles.
Air strikes would endanger civilians among whom the regime has most probably deployed such weapons.
If missiles do not result in civilian casualties, any gas inadvertently released from those weapons would likely take an even heavier toll among the very people such a mission is meant to help protect. Striking to "deny or significantly degrade" the Syrian air force's capacity to bomb civilians comes with collateral risks.
Supplying guns, ammunition and anti-tank weapons to anti-government groups would not make any real difference in the battlefields - and runs the risk of those arms ending up in the hands of jihadist brigades bent on terrorism to achieve goals even more inimical to secular interests than those of the regime.
Military intervention beyond small arms, no-fly zones and air strikes would trigger even more dangers. American "boots on the ground" would inflame radical Islamist sentiments, drawing even more jihadists from across the Middle East and minority communities in Western countries to join the war in an already deeply divided nation.
Such action would further complicate chances of a resolution not only of the conflict in Syria but also of wider regional issues. It would, for example, likely foreclose the option to negotiate the nuclear arms question with the new and more moderate President Hassan Rouhani of Iran.