That time Vladimir Putin warned the U.S. that unilateral foreign intervention 'would constitute an act of aggression'

From the outset, Russia has advocated peaceful dialogue enabling Syrians to develop a compromise plan for their own future. We are not protecting the Syrian government, but international law. We need to use the United Nations Security Council and believe that preserving law and order in today's complex and turbulent world is one of the few ways to keep international relations from sliding into chaos. The law is still the law, and we must follow it whether we like it or not. Under current international law, force is permitted only in self-defense or by the decision of the Security Council. Anything else is unacceptable under the United Nations Charter and would constitute an act of aggression. […]

We must stop using the language of force and return to the path of civilized diplomatic and political settlement. [The New York Times]