U.S. interventions since World War II led to stable democracies within ten years less than 3 percent of the time.
I doubt it, because recent research suggests that we are likely to be disappointed by the outcome. A 2006 study by Jeffrey Pickering and Mark Peceny found that military intervention by liberal states (i.e., states like Britain, France and the United States) “has only very rarely played a role in democratization since 1945.” Similarly, George Downs, and Bruce Bueno de Mesquita of New York University found that U.S. interventions since World War II led to stable democracies within ten years less than 3 percent of the time, and a separate study by their NYU colleague William Easterly and several associates found that both U.S and Soviet interventions during the Cold War generally led to “significant declines in democracy.” Finally, a 2010 article by Goran Piec and Daniel Reiter examines forty-two “foreign imposed regime changes” since 1920 and finds that when interventions “damage state infrastructural power” they also increase the risk of subsequent civil war.
The best and most relevant study I have yet read on this question is an as-yet unpublished working paper by Alexander Downes of Duke University, which you can find on his website here. Using a more sophisticated research design, Downes examined 100 cases of “foreign imposed regime change” going all the way back to 1816. In particular, his analysis takes into account “selection effects” (i.e., the fact that foreign powers are more likely to intervene in states that already have lots of problems, so you would expect these states to have more problems afterwards too). He finds that foreign intervention tends to promote stability when the intervening powers are seeking to restore a previously deposed ruler. But when foreign interveners oust an existing ruler and impose a wholly new government (which is what we are trying to do in Libya), the likelihood of civil war more than triples.5