Assertion: alliance | /r/HasProperty | informal
Facets:
Source sentences:
text: Although alliances may be informal, they are typically formalized by a treaty of alliance, the most critical clauses of which are those that define the casus foederis, or the circumstances under which the treaty obligates an ally to aid a fellow member.
text: Alliance, in international relations, a formal agreement between two or more states for mutual support in case of war.