Afghanistan
Given that the Afghan intervention had overwhelming bipartisan support both among politicans and among the general public (85-90% support among Democrats), would you care to elaborate on how "the Left" opposed this, without simply defining "the Left" as a small group of activists with little influence and less power?
Kosovo only attracted pretty sporadic opposition, and in terms of politicians much more so from Republicans than "the Left". I suspect you would have found *more* support for intervening in the Rwandan genocide among liberals than conservatives, though again, if "the Left" means five guys reading Chomsky in a Cambridge cafe, you'd have a point, if a rather unimportant one.