политический обычай(Conventions are rules that are politically but not legally binding. They are binding primarily by virtue of their acceptance by those in power. (The term "convention" literally means a 'coming together'). Conventions play a central part in the constitution. They deal with fundamental matters concerning the distribution of power and government accountability, for example the principle that the monarch must act on the advice of ministers is a convention. Thus conventions may adjust the legal rules to the political reality. NSamusev)
