I'm not a Buddhist but in my little understanding of their teaching there are very rare circumstances when killing is allowed. Motivation is extremely important.
Buddhists disagree among themselves about the scope and interpretation of the 'do not kill' precept, just as Jews and Christians have many interpretations of the analogous commandment. And individual Buddhists (like Jews and Christians) are all over the map regarding how scrupulously they adhere to their precepts. Some Buddhists are vegetarians, while other Buddhists happily eat meat. Just about every Buddhist country has a military.
I have to disagree somewhat here. In my understanding of Buddhism the strict Calvinist idea of judgement implies that actions do not have consequences and that your actions have no effect on what the judgement is.
Yeah, some of the hyper-Protestant Christian interpretations of God's grace do appear to come dangerously close to an effective denial of the importance of moral evil. It doesn't seem to matter what anybody does, even Adolph Hitler, as long as he has faith in the saving power of Jesus. Of course, these kind of Protestants would doubtless protest very loudly (and perhaps justifiably) that this is a caricature of their views. It likely is. But even so, interpreting God's forgiving grace towards sinners in such a way that it doesn't turn into a 'get out of evil free' card is a problem that Christian ethics has to address.
There is also the idea of "forgiveness of sins"; a forgiven sin may not have any consequences, or just minor consequences. Buddhism does not have the concept of "sin", replacing it with "unwise action". However, by dropping sin it also drops forgiveness of sin. Karma does not, and cannot, forgive.
Yeah, it's true.
But in the karma theory, there's no such thing as an eternal fate either. There's always the possibility of change. So a super-sinner like Adolph Hitler might find himself down there in the deepest and nastiest Buddhist hells, even if he truly and sincerely embraced religion in his last days in the bunker. His appalling acts still have to work themselves out, he still has to pay the price, so to speak.
With karma, it matters what hell beings do, what moral qualities their actions in hell have, just as if matters what we do here in this lifetime. If Hitler really did turn his life around, if he really does live as a saint among the hell beings, compassionately helping them in their extremity, he's going to start moving on an upward trajectory. He'll eventually rise up out of hell again, though that might take an awfully long time in his case. If he perserveres for as long as it takes, he could even rise into the heavens and become divine.
I guess that in Christian theological terms, interpreted in the light of the arguments about grace vs works, the karma theory emphasizes works almost exclusively. It's all about what we personally do and it places very little emphasis on beseeching higher powers to unburden us of the consequences. But because everything depends on what we do, there's always the opportunity for us to change course and to start doing something different and less blameworthy.
It doesn't have a great deal to do with the Indian ideas of karma, but it's interesting to notice that in the history of Buddhism, the pure-land Buddhists, particularly those in Japan, evolved ideas in some cases very similar to those of the Christians. There's the idea of 'other-power' (grace) and the idea that one will be surely reborn into the heavenly Pure Land of the West, whatever one's earthly sins, provided only that one sincerely calls upon the saving grace of Amida. This appears to be an independent historical development in the far east, religious convergent evolution we might say, though there were a few Nestorian Christians in China at the time, so maybe it's a faint eastern reflection of Christian ideas from far to the west.
