text: 27. In that connection, she pointed out that according to present-day international law, the binding legal force of international treaties might be terminated in four different ways: a treaty might expire, be dissolved, become void, or be cancelled. There were three grounds for dissolution: mutual consent and withdrawal, which were indispensable, and a vital change in circumstances occurring after the assumption of the obligation. The theory of changed conditions was based on the rule of Conventio omnis intellegitur rebus £j_c stantibus, or the clausula rebus sic stantibus. Two theories were advanced for the application of that rule. The first was that vital changes might occur in the position of the States which justified release from the obligations assumed. The second was that every treaty was concluded on certain assumptions, and that where, by virtue of changed conditions, a situation was created which, if it had existed at the time the treaty was signed would have induced the parties not to sign or ratify the instrument, the treaty might be dissolved. Both theories led to the conclusion that treaties might be dissolved if the conditions on which they were based no longer existed. The principle had been supported by Attorney-General Biddle in an opinion dated 28 July 1941, but according to Professor J.L. Brierly, the principle was by no means a well-established rule of international law, and even if it were recognized, it could be resorted to only in very exceptional cases, and only entitled the State concerned to request release from its obligation by the other party. The latter principle was clearly formulated in the protocol to the Treaty of London, 1871. The same rule was implicit in Article 19 of the Covenant of the League of Nations and it had been a 
analysis: The text appears to be discussing the termination of international treaties, specifically the grounds for dissolution and the principles involved. The language used is formal and legal, and the concepts discussed are related to international law and diplomacy. This suggests that the text may be related to the international relations or law category.