The overall principle that he supports the need for wealthy Americans to pay their fair share I think has been established many times by him in a variety of forums.

WHITEHOUSE: Press Briefing

Efforts to enhance overall future compliance should forever be a guiding principle of our system of tax administration.

FORBES: New Streamlined Filing Compliance Procedures for Non-Resident U.S. Taxpayers

Pro-fossil-fuel groups argue that if using renewables is more expensive, that has an overall negative impact on growth which should, in principle, curb employment.

BBC: Is Keystone a Touchstone?

It's not a -- it's a principle that should guide a tax reform -- overall tax reform structure.

WHITEHOUSE: Press Briefing

In principle, the pre-budget report will not discuss the overall spending plans of individual departments.

BBC: What is a pre-budget report?