on principle

The social system of the West is based on the democratic principle.

Kind of works on the same principle as your car key does.

A lot of people in life don't stand on their principles.

Until recently, they have pretty much worked on the same principles.

It would have given too much away on the legal principle.

The value of money is determined on exactly the same principles as any other financial security.

America was built on the democratic principle, and what is more American than football, right?

It is based on the principle of between hard and soft.

And how great to see any fashion company these days stand on a principle.

Then there were more books on the general principles of putting such things together into systems.