That the Ecological Footprint is a controversial concept with many criticisms.

Identity politics is a controversial concept, subject to a range of critiques.

However, sustainable development is a recent, controversial concept.

For historians of the Expressionist period, the stadtkrone has long been a controversial concept.

"Heritage" is a more controversial concept than it sometimes appears.

By Aristotle's own account, this is a difficult and controversial concept.

Mental age was once considered a controversial concept.

Call of Duty: Elite has been a controversial concept since its announcement earlier this year.

In addition, vague, controversial concepts like 'self-governance' and 'cultural autonomy' also have the potential to cause conflict.

Throughout its recent history, eugenics remains a controversial concept.