Over at The National Interest, a pair of essays, one by John Mearsheimer and a response by David Adesnik, grapple with the questions as to when and under what conditions the United States ought to intervene (militarily) in other countries and whether such intervention tends to produce successful results. Over at the New Yorker, Jon Lee Anderson surveys a decade of U.S. activism in the Middle East, concludes that we have left the area in a worse state as a result, starting with the Iraq War of 2003, yet asks whether there is a "plan of action" to address the unraveling of the region.
Behind the strategic considerations, there are ethical ones as well. The current issue of Ethics and International Affairs has an entire symposium devoted to the question of whether armed rebellions are just. Yet while this can often be assessed after the fact, as James Turner Johnson notes in his contribution, the standard often cited by ethicists "gives no clear guidance for judging a particular resistance or revolutionary effort while it is under way," and the same might be said of interventions as well.
The policymaker has two initial approaches, the "morality of intentions" versus the "morality of results." For the latter, of course, time frame becomes very important--at what point are the "results" to be assessed? If, as Zhou Enlai famously put it, it was "too soon" two centuries after the French Revolution to assess its impact, then his standard is of no use to the policymaker. So where should the line be drawn? For supporters of the Iraq War or Libya intervention, the cutting off point for assessing results came relatively soon after operations began--the pulling down of the Saddam statue or Saddam's own capture, or the seizure of Tripoli by the interim government or the death of Muammar Gadhafi, while critics point to the ongoing disorder in both countries and the general record of instability and loss of life in the subsequent years since regime change occurred to argue that the overall interventions were not justified (and perhaps were not ethical).
What about proportionality of response? If the intervention is likely to cause as much or more harm than what it seeks to prevent or avoid, is it an ethical course of action? By that token, should the odds of intervention favor a successful outcome? If an intervention is likely to fail to achieve its stated goals (particularly if they are humanitarian ones) and will cause greater damage and destruction in the process, should it be authorized? (These are some of the questions which Ned Dobos grappled with in his contribution to EIA in 2012.)
There is no easy counsel to offer policymakers. As C. A. J. Coady noted in a report for the U.S. Institute of Peace, the question about whether or not to intervene "is bedeviled by the problems discussed above." And whatever decisions are taken--intervention (as in the case of Iraq or Libya) or non-intervention (as in the case of Syria and South Sudan)--will be criticized on both strategic and ethical grounds.
[This post reflects my own personal reflections on the subject.]