of principle

基本解释

You must state your position on matters of principle. Don't be equivocal.
在原则问题上要表明你的态度，不要依违两可。
《新英汉大辞典》
He is a man of honor as well as a man of principle, and so he has, ever since he got into politics, been doing something about it.
他是一个有原则的人，也是一个正直的人，所以，自从他踏入政坛那一刻起他就一直在做与此有关的事情。
What was agreed to at the JCCT were important statements of principle and policy – but they must be turned into concrete action with results.
在美中商贸联委会上达成的一致都是原则和政策上的重要声明——但它们必须转化为具体行动，取得成果。

The journalist says he is not a hero, but rather a man of principle.
Of course, that's not the useful application for it, it's more of a proof of principle, but it does show you that you can put it in for studies in any organisms.
当然，这不是很有用的应用，这仅仅是一个原理上的证明，但它告诉你你可以把它,放到研究任何生物体中。
麻省理工公开课 - 化学原理课程节选
The first sort of principle to me is clipping coupons.
我的第一个原则就是定期获得收益。
耶鲁公开课 - 金融市场课程节选

He is a man of principle, but his principles are neither unwavering nor always coherent.
ECONOMIST: John McCain