So what is your red line? If Iran used a nuke and killed 1 million of it's own people

[Posteritatis]

150. Definitely not just the US

Britain and France have both been having the same discussion, for example, and I know it's going on in other places as well. My own prime minister's just a pissant little warmonger who I generally dismiss on those fronts, and Canada has little ability to do much heavy lifting abroad, but there's been a lot of discussion over the last generation here about where our own lines are, what we should be willing to get involved with when the bigger powers get interventionist, and how far we should be willing to take that. Our 2004 election was largely fought over that question, and it's coming up in the media again quite a bit (even though we're certain to be sitting this one out no matter what happens).

Other, more obscure countries have found positions they're comfortable with getting involved with; you never hear about Nepalese or Tanzanian soldiers wading into the CNN-interrupting military interventions, for instance, but they've got 2,250 soldiers between them in a shooting war right now, trying to impose or restore some semblance of sanity in Congo.

While the situations that bring the argument up are universally horrible, I'm quite okay with countries rehashing the question regularly, since it's an extremely important one.