I like to think, like the next guy (or gal), that I have principles. Do steal, don't lie, don't cheat. That's what my mother told me. But when she caught me smoking in my room two nights in a row... I told her that Confucius said that sometimes we should lie. She didn't believe me. So we both read through Confucius for a couple of days until one of us found it.
In Buddhism, there is talk of using "skillful means." Does this mean to lie, steal, and cheat? Maybe. If it is the only way to help someone move along the Way.
There is another Buddhist saying that one should not be attached to their preferences. Are preferences "principles." Kindof, sortof. Aren't they?
My mother-in-law said that she votes Republican, no matter what. Even if her favorite granddaughter (she only has one) is running on the Democratic ticket. Geeze, I'd vote for any party if my daughter was running. But then I might try to persuade her not to tow the party line.
I recently wrote about GE and the fact that they didn't pay taxes. Some have principles that rich companies should pay lots of taxes. I'm more of the elk that if they figure out how not to pay taxes, so much the better. But I'm not an advocate of big government.
Or war... but, throwing out principles, I love to see situations where mass murders are averted by military action (if that really was the case in Libya).
So how do we act, without principles? Well, we weight the benefits and consequences of each action and see what is worse... or better. What is difficult is that the signposts are not clearly marked.